def resolve_freezer(freezer):
<EOL>if not freezer:<EOL><INDENT>return _Default()<EOL><DEDENT>if isinstance(freezer, six.string_types):<EOL><INDENT>cls = _freezer_lookup(freezer)<EOL>return cls()<EOL><DEDENT>if freezer.__class__ == type.__class__:<EOL><INDENT>return freezer()<EOL><DEDENT>if freezer not in FREEZER.ALL:<EOL><INDENT>warn(u"<STR_LIT>".format(freezer))<EOL><DEDENT>return freezer<EOL>
Locate the appropriate freezer given FREEZER or string input from the programmer.

:param freezer: FREEZER constant or string for the freezer that is requested.  (None = FREEZER.DEFAULT)
:return: