def get_sources(self, component_id):
<EOL>StreamId = namedtuple('<STR_LIT>', '<STR_LIT>')<EOL>if component_id in self.inputs:<EOL><INDENT>ret = {}<EOL>for istream in self.inputs.get(component_id):<EOL><INDENT>key = StreamId(id=istream.stream.id, component_name=istream.stream.component_name)<EOL>ret[key] = istream.gtype<EOL><DEDENT>return ret<EOL><DEDENT>else:<EOL><INDENT>return None<EOL><DEDENT>
Returns the declared inputs to specified component

        :return: map <streamId namedtuple (same structure as protobuf msg) -> gtype>, or
                 None if not found