'Remove unspecified parameters from the dictionary.
This function removes unspecified parameters from the dictionary.
This method checks only root-level keys from a ref dictionary.
:param ref: a dictionary representing deserialized response to be
serialized'

@classmethod
def filter_params(cls, ref):

    ref_keys = set(ref.keys())
    blocked_keys = (ref_keys - cls._public_parameters)
    for blocked_param in blocked_keys:
        del ref[blocked_param]
    return ref
