returns a dictionary of properties assigned to the class

def list_properties(cls):
    """ returns a dictionary of properties assigned to the class"""
    rtn_dict = {}
    for attr in dir(cls):
        if attr not in ["properties", "__doc__", "doc"]:
            attr_val = getattr(cls, attr)

            if isinstance(attr_val, MODULE.rdfclass.RdfPropertyMeta):
                rtn_dict[attr] = attr_val
    return rtn_dict