code: def _whitelist_standard_flask_kwargs(cls, kwargs):
          
          # prevent any copy shenanigans from happening
          kwargs = deepcopy(kwargs)
  
          if not cls._flask_init_argspec_cache:
              cls._flask_init_argspec_cache = inspect.getargspec(Flask.__init__)
  
          return {key: val for key, val in iteritems(kwargs)
                  if key in cls._flask_init_argspec_cache.args}
docs: Whitelist a dictionary of kwargs to remove any that are not valid
          for Flask's ``__init__`` constructor.
  
          Since many Fleaker app mixins define their own kwargs for use in
          construction and Flask itself does not accept ``**kwargs``, we need to
          whitelist anything unknown.
  
          Uses the proper argspec from the :meth:`flask.Flask.__init__` so it
          should handle all args.
  
          Args:
              kwargs (dict): The dictionary of kwargs you want to whitelist.
  
          Returns:
              dict: The whitelisted dictionary of kwargs.