Implements the command line interface `butler define-visits` subcommand,
should only be called by command line tools and unit test code that tests
this function.
Defines visits from exposures in the butler registry
Parameters
----------
repo : `str`
URI to the location to create the repo.
config_file : `str` or `None`
Path to a config file that contains overrides to the ingest config.
collections : `list` [`str`]
An expression specifying the collections to be searched (in order) when
reading datasets, and optionally dataset type restrictions on them.
insrument : `str`
The name or fully-qualified class name of an instrument.
Definition at line 27 of file defineVisits.py.