r"""
    returns a copy of dict_ without keys in the negative_keys list

    Args:
        dict_ (dict):
        negative_keys (list):

def dict_setdiff(dict_, negative_keys):
    r"""
    returns a copy of dict_ without keys in the negative_keys list

    Args:
        dict_ (dict):
        negative_keys (list):
    """
    keys = [key for key in six.iterkeys(dict_)
            if key not in set(negative_keys)]
    subdict_ = dict_subset(dict_, keys)
    return subdict_