Coverage for python/lsst/daf/butler/core/storageClass.py: 47%
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1# This file is part of daf_butler.
2#
3# Developed for the LSST Data Management System.
4# This product includes software developed by the LSST Project
5# (http://www.lsst.org).
6# See the COPYRIGHT file at the top-level directory of this distribution
7# for details of code ownership.
8#
9# This program is free software: you can redistribute it and/or modify
10# it under the terms of the GNU General Public License as published by
11# the Free Software Foundation, either version 3 of the License, or
12# (at your option) any later version.
13#
14# This program is distributed in the hope that it will be useful,
15# but WITHOUT ANY WARRANTY; without even the implied warranty of
16# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
17# GNU General Public License for more details.
18#
19# You should have received a copy of the GNU General Public License
20# along with this program. If not, see <http://www.gnu.org/licenses/>.
22from __future__ import annotations
24"""Support for Storage Classes."""
26__all__ = ("StorageClass", "StorageClassFactory", "StorageClassConfig")
28import builtins
29import copy
30import logging
32from typing import (
33 Any,
34 Collection,
35 Dict,
36 List,
37 Mapping,
38 Optional,
39 Set,
40 Sequence,
41 Tuple,
42 Type,
43 Union,
44)
46from lsst.utils import doImportType
47from lsst.utils.introspection import get_full_type_name
48from lsst.utils.classes import Singleton
49from .storageClassDelegate import StorageClassDelegate
50from .config import ConfigSubset, Config
51from .configSupport import LookupKey
53log = logging.getLogger(__name__)
56class StorageClassConfig(ConfigSubset):
57 """Configuration class for defining Storage Classes."""
59 component = "storageClasses"
60 defaultConfigFile = "storageClasses.yaml"
63class StorageClass:
64 """Class describing how a label maps to a particular Python type.
66 Parameters
67 ----------
68 name : `str`
69 Name to use for this class.
70 pytype : `type` or `str`
71 Python type (or name of type) to associate with the `StorageClass`
72 components : `dict`, optional
73 `dict` mapping name of a component to another `StorageClass`.
74 derivedComponents : `dict`, optional
75 `dict` mapping name of a derived component to another `StorageClass`.
76 parameters : `~collections.abc.Sequence` or `~collections.abc.Set`
77 Parameters understood by this `StorageClass` that can control
78 reading of data from datastores.
79 delegate : `str`, optional
80 Fully qualified name of class supporting assembly and disassembly
81 of a `pytype` instance.
82 converters : `dict` [`str`, `str`], optional
83 Mapping of python type to function that can be called to convert
84 that python type to the valid type of this storage class.
85 """
87 _cls_name: str = "BaseStorageClass"
88 _cls_components: Optional[Dict[str, StorageClass]] = None
89 _cls_derivedComponents: Optional[Dict[str, StorageClass]] = None
90 _cls_parameters: Optional[Union[Set[str], Sequence[str]]] = None
91 _cls_delegate: Optional[str] = None
92 _cls_pytype: Optional[Union[Type, str]] = None
93 _cls_converters: Optional[Dict[str, str]] = None
94 defaultDelegate: Type = StorageClassDelegate
95 defaultDelegateName: str = get_full_type_name(defaultDelegate)
97 def __init__(self, name: Optional[str] = None,
98 pytype: Optional[Union[Type, str]] = None,
99 components: Optional[Dict[str, StorageClass]] = None,
100 derivedComponents: Optional[Dict[str, StorageClass]] = None,
101 parameters: Optional[Union[Sequence, Set]] = None,
102 delegate: Optional[str] = None,
103 converters: Optional[Dict[str, str]] = None):
104 if name is None:
105 name = self._cls_name
106 if pytype is None: 106 ↛ 108line 106 didn't jump to line 108, because the condition on line 106 was never false
107 pytype = self._cls_pytype
108 if components is None: 108 ↛ 110line 108 didn't jump to line 110, because the condition on line 108 was never false
109 components = self._cls_components
110 if derivedComponents is None: 110 ↛ 112line 110 didn't jump to line 112, because the condition on line 110 was never false
111 derivedComponents = self._cls_derivedComponents
112 if parameters is None: 112 ↛ 114line 112 didn't jump to line 114, because the condition on line 112 was never false
113 parameters = self._cls_parameters
114 if delegate is None: 114 ↛ 118line 114 didn't jump to line 118, because the condition on line 114 was never false
115 delegate = self._cls_delegate
117 # Merge converters with class defaults.
118 self._converters = {}
119 if self._cls_converters is not None:
120 self._converters.update(self._cls_converters)
121 if converters: 121 ↛ 122line 121 didn't jump to line 122, because the condition on line 121 was never true
122 self._converters.update(converters)
124 # Version of converters where the python types have been
125 # Do not try to import anything until needed.
126 self._converters_by_type: Optional[Dict[Type, Type]] = None
128 self.name = name
130 if pytype is None:
131 pytype = object
133 self._pytype: Optional[Type]
134 if not isinstance(pytype, str):
135 # Already have a type so store it and get the name
136 self._pytypeName = get_full_type_name(pytype)
137 self._pytype = pytype
138 else:
139 # Store the type name and defer loading of type
140 self._pytypeName = pytype
141 self._pytype = None
143 if components is not None:
144 if len(components) == 1: 144 ↛ 145line 144 didn't jump to line 145, because the condition on line 144 was never true
145 raise ValueError(f"Composite storage class {name} is not allowed to have"
146 f" only one component '{next(iter(components))}'."
147 " Did you mean it to be a derived component?")
148 self._components = components
149 else:
150 self._components = {}
151 self._derivedComponents = derivedComponents if derivedComponents is not None else {}
152 self._parameters = frozenset(parameters) if parameters is not None else frozenset()
153 # if the delegate is not None also set it and clear the default
154 # delegate
155 self._delegate: Optional[Type]
156 self._delegateClassName: Optional[str]
157 if delegate is not None:
158 self._delegateClassName = delegate
159 self._delegate = None
160 elif components is not None: 160 ↛ 163line 160 didn't jump to line 163, because the condition on line 160 was never true
161 # We set a default delegate for composites so that a class is
162 # guaranteed to support something if it is a composite.
163 log.debug("Setting default delegate for %s", self.name)
164 self._delegate = self.defaultDelegate
165 self._delegateClassName = self.defaultDelegateName
166 else:
167 self._delegate = None
168 self._delegateClassName = None
170 @property
171 def components(self) -> Dict[str, StorageClass]:
172 """Return the components associated with this `StorageClass`."""
173 return self._components
175 @property
176 def derivedComponents(self) -> Dict[str, StorageClass]:
177 """Return derived components associated with `StorageClass`."""
178 return self._derivedComponents
180 @property
181 def converters(self) -> Dict[str, str]:
182 """Return the type converters supported by this `StorageClass`."""
183 return self._converters
185 @property
186 def converters_by_type(self) -> Dict[Type, Type]:
187 """Return the type converters as python types."""
188 if self._converters_by_type is None:
189 self._converters_by_type = {}
191 # Loop over list because the dict can be edited in loop.
192 for candidate_type_str, converter_str in list(self.converters.items()):
193 if hasattr(builtins, candidate_type_str):
194 candidate_type = getattr(builtins, candidate_type_str)
195 else:
196 try:
197 candidate_type = doImportType(candidate_type_str)
198 except ImportError as e:
199 log.warning("Unable to import type %s associated with storage class %s (%s)",
200 candidate_type_str, self.name, e)
201 del self.converters[candidate_type_str]
202 continue
204 try:
205 converter = doImportType(converter_str)
206 except ImportError as e:
207 log.warning("Unable to import conversion function %s associated with storage class %s "
208 "required to convert type %s (%s)",
209 converter_str, self.name, candidate_type_str, e)
210 del self.converters[candidate_type_str]
211 continue
212 if not callable(converter):
213 # doImportType is annotated to return a Type but in actual
214 # fact it can return Any except ModuleType because package
215 # variables can be accessed. This make mypy believe it
216 # is impossible for the return value to not be a callable
217 # so we must ignore the warning.
218 log.warning("Conversion function %s associated with storage class %s to " # type: ignore
219 "convert type %s is not a callable.", converter_str, self.name,
220 candidate_type_str)
221 del self.converters[candidate_type_str]
222 continue
223 self._converters_by_type[candidate_type] = converter
224 return self._converters_by_type
226 @property
227 def parameters(self) -> Set[str]:
228 """Return `set` of names of supported parameters."""
229 return set(self._parameters)
231 @property
232 def pytype(self) -> Type:
233 """Return Python type associated with this `StorageClass`."""
234 if self._pytype is not None:
235 return self._pytype
237 if hasattr(builtins, self._pytypeName):
238 pytype = getattr(builtins, self._pytypeName)
239 else:
240 pytype = doImportType(self._pytypeName)
241 self._pytype = pytype
242 return self._pytype
244 @property
245 def delegateClass(self) -> Optional[Type]:
246 """Class to use to delegate type-specific actions."""
247 if self._delegate is not None:
248 return self._delegate
249 if self._delegateClassName is None:
250 return None
251 delegate_class = doImportType(self._delegateClassName)
252 self._delegate = delegate_class
253 return self._delegate
255 def allComponents(self) -> Mapping[str, StorageClass]:
256 """Return all defined components.
258 This mapping includes all the derived and read/write components
259 for the corresponding storage class.
261 Returns
262 -------
263 comp : `dict` of [`str`, `StorageClass`]
264 The component name to storage class mapping.
265 """
266 components = copy.copy(self.components)
267 components.update(self.derivedComponents)
268 return components
270 def delegate(self) -> StorageClassDelegate:
271 """Return an instance of a storage class delegate.
273 Returns
274 -------
275 delegate : `StorageClassDelegate`
276 Instance of the delegate associated with this `StorageClass`.
277 The delegate is constructed with this `StorageClass`.
279 Raises
280 ------
281 TypeError
282 This StorageClass has no associated delegate.
283 """
284 cls = self.delegateClass
285 if cls is None:
286 raise TypeError(f"No delegate class is associated with StorageClass {self.name}")
287 return cls(storageClass=self)
289 def isComposite(self) -> bool:
290 """Return Boolean indicating whether this is a composite or not.
292 Returns
293 -------
294 isComposite : `bool`
295 `True` if this `StorageClass` is a composite, `False`
296 otherwise.
297 """
298 if self.components:
299 return True
300 return False
302 def _lookupNames(self) -> Tuple[LookupKey, ...]:
303 """Keys to use when looking up this DatasetRef in a configuration.
305 The names are returned in order of priority.
307 Returns
308 -------
309 names : `tuple` of `LookupKey`
310 Tuple of a `LookupKey` using the `StorageClass` name.
311 """
312 return (LookupKey(name=self.name), )
314 def knownParameters(self) -> Set[str]:
315 """Return set of all parameters known to this `StorageClass`.
317 The set includes parameters understood by components of a composite.
319 Returns
320 -------
321 known : `set`
322 All parameter keys of this `StorageClass` and the component
323 storage classes.
324 """
325 known = set(self._parameters)
326 for sc in self.components.values():
327 known.update(sc.knownParameters())
328 return known
330 def validateParameters(self, parameters: Collection = None) -> None:
331 """Check that the parameters are known to this `StorageClass`.
333 Does not check the values.
335 Parameters
336 ----------
337 parameters : `~collections.abc.Collection`, optional
338 Collection containing the parameters. Can be `dict`-like or
339 `set`-like. The parameter values are not checked.
340 If no parameters are supplied, always returns without error.
342 Raises
343 ------
344 KeyError
345 Some parameters are not understood by this `StorageClass`.
346 """
347 # No parameters is always okay
348 if not parameters:
349 return
351 # Extract the important information into a set. Works for dict and
352 # list.
353 external = set(parameters)
355 diff = external - self.knownParameters()
356 if diff:
357 s = "s" if len(diff) > 1 else ""
358 unknown = '\', \''.join(diff)
359 raise KeyError(f"Parameter{s} '{unknown}' not understood by StorageClass {self.name}")
361 def filterParameters(self, parameters: Dict[str, Any],
362 subset: Collection = None) -> Dict[str, Any]:
363 """Filter out parameters that are not known to this `StorageClass`.
365 Parameters
366 ----------
367 parameters : `dict`, optional
368 Candidate parameters. Can be `None` if no parameters have
369 been provided.
370 subset : `~collections.abc.Collection`, optional
371 Subset of supported parameters that the caller is interested
372 in using. The subset must be known to the `StorageClass`
373 if specified. If `None` the supplied parameters will all
374 be checked, else only the keys in this set will be checked.
376 Returns
377 -------
378 filtered : `dict`
379 Valid parameters. Empty `dict` if none are suitable.
381 Raises
382 ------
383 ValueError
384 Raised if the provided subset is not a subset of the supported
385 parameters or if it is an empty set.
386 """
387 if not parameters:
388 return {}
390 known = self.knownParameters()
392 if subset is not None:
393 if not subset:
394 raise ValueError("Specified a parameter subset but it was empty")
395 subset = set(subset)
396 if not subset.issubset(known):
397 raise ValueError(f"Requested subset ({subset}) is not a subset of"
398 f" known parameters ({known})")
399 wanted = subset
400 else:
401 wanted = known
403 return {k: parameters[k] for k in wanted if k in parameters}
405 def validateInstance(self, instance: Any) -> bool:
406 """Check that the supplied Python object has the expected Python type.
408 Parameters
409 ----------
410 instance : `object`
411 Object to check.
413 Returns
414 -------
415 isOk : `bool`
416 True if the supplied instance object can be handled by this
417 `StorageClass`, False otherwise.
418 """
419 return isinstance(instance, self.pytype)
421 def can_convert(self, other: StorageClass) -> bool:
422 """Return `True` if this storage class can convert python types
423 in the other storage class.
425 Parameters
426 ----------
427 other : `StorageClass`
428 The storage class to check.
430 Returns
431 -------
432 can : `bool`
433 `True` if the two storage classes are compatible.
434 """
435 if other.name == self.name:
436 # Identical storage classes are compatible.
437 return True
439 for candidate_type in self.converters_by_type:
440 if issubclass(other.pytype, candidate_type):
441 return True
442 return False
444 def coerce_type(self, incorrect: Any) -> Any:
445 """Coerce the supplied incorrect instance to the python type
446 associated with this `StorageClass`.
448 Parameters
449 ----------
450 incorrect : `object`
451 An object that might be the incorrect type.
453 Returns
454 -------
455 correct : `object`
456 An object that matches the python type of this `StorageClass`.
457 Can be the same object as given. If `None`, `None` will be
458 returned.
460 Raises
461 ------
462 TypeError
463 Raised if no conversion can be found.
464 """
465 if incorrect is None:
466 return None
468 # Possible this is the correct type already.
469 if self.validateInstance(incorrect):
470 return incorrect
472 # Check each registered converter.
473 for candidate_type, converter in self.converters_by_type.items():
474 if isinstance(incorrect, candidate_type):
475 try:
476 return converter(incorrect)
477 except Exception:
478 log.error("Converter %s failed to convert type %s",
479 get_full_type_name(converter), get_full_type_name(incorrect))
480 raise
481 raise TypeError("Type does not match and no valid converter found to convert"
482 f" '{type(incorrect)}' to '{self.pytype}'")
484 def __eq__(self, other: Any) -> bool:
485 """Equality checks name, pytype name, delegate name, and components."""
486 if not isinstance(other, StorageClass):
487 return NotImplemented
489 if self.name != other.name:
490 return False
492 # We must compare pytype and delegate by name since we do not want
493 # to trigger an import of external module code here
494 if self._delegateClassName != other._delegateClassName:
495 return False
496 if self._pytypeName != other._pytypeName:
497 return False
499 # Ensure we have the same component keys in each
500 if set(self.components.keys()) != set(other.components.keys()):
501 return False
503 # Same parameters
504 if self.parameters != other.parameters:
505 return False
507 # Ensure that all the components have the same type
508 for k in self.components:
509 if self.components[k] != other.components[k]:
510 return False
512 # If we got to this point everything checks out
513 return True
515 def __hash__(self) -> int:
516 return hash(self.name)
518 def __repr__(self) -> str:
519 optionals: Dict[str, Any] = {}
520 if self._pytypeName != "object":
521 optionals["pytype"] = self._pytypeName
522 if self._delegateClassName is not None:
523 optionals["delegate"] = self._delegateClassName
524 if self._parameters:
525 optionals["parameters"] = self._parameters
526 if self.components:
527 optionals["components"] = self.components
528 if self.converters:
529 optionals["converters"] = self.converters
531 # order is preserved in the dict
532 options = ", ".join(f"{k}={v!r}" for k, v in optionals.items())
534 # Start with mandatory fields
535 r = f"{self.__class__.__name__}({self.name!r}"
536 if options:
537 r = r + ", " + options
538 r = r + ")"
539 return r
541 def __str__(self) -> str:
542 return self.name
545class StorageClassFactory(metaclass=Singleton):
546 """Factory for `StorageClass` instances.
548 This class is a singleton, with each instance sharing the pool of
549 StorageClasses. Since code can not know whether it is the first
550 time the instance has been created, the constructor takes no arguments.
551 To populate the factory with storage classes, a call to
552 `~StorageClassFactory.addFromConfig()` should be made.
554 Parameters
555 ----------
556 config : `StorageClassConfig` or `str`, optional
557 Load configuration. In a ButlerConfig` the relevant configuration
558 is located in the ``storageClasses`` section.
559 """
561 def __init__(self, config: Optional[Union[StorageClassConfig, str]] = None):
562 self._storageClasses: Dict[str, StorageClass] = {}
563 self._configs: List[StorageClassConfig] = []
565 # Always seed with the default config
566 self.addFromConfig(StorageClassConfig())
568 if config is not None: 568 ↛ 569line 568 didn't jump to line 569, because the condition on line 568 was never true
569 self.addFromConfig(config)
571 def __str__(self) -> str:
572 """Return summary of factory.
574 Returns
575 -------
576 summary : `str`
577 Summary of the factory status.
578 """
579 sep = "\n"
580 return f"""Number of registered StorageClasses: {len(self._storageClasses)}
582StorageClasses
583--------------
584{sep.join(f"{s}: {self._storageClasses[s]}" for s in self._storageClasses)}
585"""
587 def __contains__(self, storageClassOrName: Union[StorageClass, str]) -> bool:
588 """Indicate whether the storage class exists in the factory.
590 Parameters
591 ----------
592 storageClassOrName : `str` or `StorageClass`
593 If `str` is given existence of the named StorageClass
594 in the factory is checked. If `StorageClass` is given
595 existence and equality are checked.
597 Returns
598 -------
599 in : `bool`
600 True if the supplied string is present, or if the supplied
601 `StorageClass` is present and identical.
603 Notes
604 -----
605 The two different checks (one for "key" and one for "value") based on
606 the type of the given argument mean that it is possible for
607 StorageClass.name to be in the factory but StorageClass to not be
608 in the factory.
609 """
610 if isinstance(storageClassOrName, str): 610 ↛ 612line 610 didn't jump to line 612, because the condition on line 610 was never false
611 return storageClassOrName in self._storageClasses
612 elif isinstance(storageClassOrName, StorageClass):
613 if storageClassOrName.name in self._storageClasses:
614 return storageClassOrName == self._storageClasses[storageClassOrName.name]
615 return False
617 def addFromConfig(self, config: Union[StorageClassConfig, Config, str]) -> None:
618 """Add more `StorageClass` definitions from a config file.
620 Parameters
621 ----------
622 config : `StorageClassConfig`, `Config` or `str`
623 Storage class configuration. Can contain a ``storageClasses``
624 key if part of a global configuration.
625 """
626 sconfig = StorageClassConfig(config)
627 self._configs.append(sconfig)
629 # Since we can not assume that we will get definitions of
630 # components or parents before their classes are defined
631 # we have a helper function that we can call recursively
632 # to extract definitions from the configuration.
633 def processStorageClass(name: str, sconfig: StorageClassConfig) -> None:
634 # Maybe we've already processed this through recursion
635 if name not in sconfig:
636 return
637 info = sconfig.pop(name)
639 # Always create the storage class so we can ensure that
640 # we are not trying to overwrite with a different definition
641 components = None
643 # Extract scalar items from dict that are needed for
644 # StorageClass Constructor
645 storageClassKwargs = {k: info[k] for k in ("pytype", "delegate", "parameters") if k in info}
647 if "converters" in info:
648 storageClassKwargs["converters"] = info["converters"].toDict()
650 for compName in ("components", "derivedComponents"):
651 if compName not in info:
652 continue
653 components = {}
654 for cname, ctype in info[compName].items():
655 if ctype not in self:
656 processStorageClass(ctype, sconfig)
657 components[cname] = self.getStorageClass(ctype)
659 # Fill in other items
660 storageClassKwargs[compName] = components
662 # Create the new storage class and register it
663 baseClass = None
664 if "inheritsFrom" in info:
665 baseName = info["inheritsFrom"]
666 if baseName not in self: 666 ↛ 667line 666 didn't jump to line 667, because the condition on line 666 was never true
667 processStorageClass(baseName, sconfig)
668 baseClass = type(self.getStorageClass(baseName))
670 newStorageClassType = self.makeNewStorageClass(name, baseClass, **storageClassKwargs)
671 newStorageClass = newStorageClassType()
672 self.registerStorageClass(newStorageClass)
674 for name in list(sconfig.keys()):
675 processStorageClass(name, sconfig)
677 @staticmethod
678 def makeNewStorageClass(name: str,
679 baseClass: Optional[Type[StorageClass]] = StorageClass,
680 **kwargs: Any) -> Type[StorageClass]:
681 """Create a new Python class as a subclass of `StorageClass`.
683 Parameters
684 ----------
685 name : `str`
686 Name to use for this class.
687 baseClass : `type`, optional
688 Base class for this `StorageClass`. Must be either `StorageClass`
689 or a subclass of `StorageClass`. If `None`, `StorageClass` will
690 be used.
692 Returns
693 -------
694 newtype : `type` subclass of `StorageClass`
695 Newly created Python type.
696 """
697 if baseClass is None:
698 baseClass = StorageClass
699 if not issubclass(baseClass, StorageClass): 699 ↛ 700line 699 didn't jump to line 700, because the condition on line 699 was never true
700 raise ValueError(f"Base class must be a StorageClass not {baseClass}")
702 # convert the arguments to use different internal names
703 clsargs = {f"_cls_{k}": v for k, v in kwargs.items() if v is not None}
704 clsargs["_cls_name"] = name
706 # Some container items need to merge with the base class values
707 # so that a child can inherit but override one bit.
708 # lists (which you get from configs) are treated as sets for this to
709 # work consistently.
710 for k in ("components", "parameters", "derivedComponents", "converters"):
711 classKey = f"_cls_{k}"
712 if classKey in clsargs:
713 baseValue = getattr(baseClass, classKey, None)
714 if baseValue is not None:
715 currentValue = clsargs[classKey]
716 if isinstance(currentValue, dict): 716 ↛ 719line 716 didn't jump to line 719, because the condition on line 716 was never false
717 newValue = baseValue.copy()
718 else:
719 newValue = set(baseValue)
720 newValue.update(currentValue)
721 clsargs[classKey] = newValue
723 # If we have parameters they should be a frozen set so that the
724 # parameters in the class can not be modified.
725 pk = "_cls_parameters"
726 if pk in clsargs:
727 clsargs[pk] = frozenset(clsargs[pk])
729 return type(f"StorageClass{name}", (baseClass,), clsargs)
731 def getStorageClass(self, storageClassName: str) -> StorageClass:
732 """Get a StorageClass instance associated with the supplied name.
734 Parameters
735 ----------
736 storageClassName : `str`
737 Name of the storage class to retrieve.
739 Returns
740 -------
741 instance : `StorageClass`
742 Instance of the correct `StorageClass`.
744 Raises
745 ------
746 KeyError
747 The requested storage class name is not registered.
748 """
749 return self._storageClasses[storageClassName]
751 def registerStorageClass(self, storageClass: StorageClass) -> None:
752 """Store the `StorageClass` in the factory.
754 Will be indexed by `StorageClass.name` and will return instances
755 of the supplied `StorageClass`.
757 Parameters
758 ----------
759 storageClass : `StorageClass`
760 Type of the Python `StorageClass` to register.
762 Raises
763 ------
764 ValueError
765 If a storage class has already been registered with
766 storageClassName and the previous definition differs.
767 """
768 if storageClass.name in self._storageClasses: 768 ↛ 769line 768 didn't jump to line 769, because the condition on line 768 was never true
769 existing = self.getStorageClass(storageClass.name)
770 if existing != storageClass:
771 raise ValueError(f"New definition for StorageClass {storageClass.name} ({storageClass}) "
772 f"differs from current definition ({existing})")
773 else:
774 self._storageClasses[storageClass.name] = storageClass
776 def _unregisterStorageClass(self, storageClassName: str) -> None:
777 """Remove the named StorageClass from the factory.
779 Parameters
780 ----------
781 storageClassName : `str`
782 Name of storage class to remove.
784 Raises
785 ------
786 KeyError
787 The named storage class is not registered.
789 Notes
790 -----
791 This method is intended to simplify testing of StorageClassFactory
792 functionality and it is not expected to be required for normal usage.
793 """
794 del self._storageClasses[storageClassName]