def on_recv(self, callback):
        raise NotImplementedError()
get full pkg path like "encoding/json" for json, pkg could be an alias
dataset/ETHPy150Open saltstack/salt/salt/transport/client.py/AsyncPubChannel.on_recv--crossover with--dataset/ETHPy150Open jtdeng/GoToDoc/GoToDoc.py/get_full_pkg