Attempt to extract a frame for displaying a product called ``name``
from the ``debugDisplay`` variable.
Per the above, an instance of `Info` can return an arbitrary object
(or nothing) as its ``display`` attribute. It is convenient -- though not
required -- that it be a dictionary mapping data products to frame
numbers, as shown in the `lsstDebug.Info` example. Given such a dictionary,
this function extracts and returns the appropriate frame number. If
``debugDisplay`` is not a collection, or if ``name`` is not found within
it, we return `None`.
Parameters
----------
debugDisplay : `object`
The contents of ``lsstDebug.Info(__name__).display``.
name : `str`
The name of the data product to be displayed.
Returns
-------
frame : `int`
A frame number, or `None`.
Definition at line 95 of file lsstDebug.py.