code: def get_user(self,nick_or_jid,create=False):
          
          if isinstance(nick_or_jid,JID):
              if not nick_or_jid.resource:
                  return None
              for u in self.users.values():
                  if nick_or_jid in (u.room_jid,u.real_jid):
                      return u
              if create:
                  return MucRoomUser(nick_or_jid)
              else:
                  return None
          return self.users.get(nick_or_jid)
docs: Get a room user with given nick or JID.
  
          :Parameters:
              - `nick_or_jid`: the nickname or room JID of the user requested.
              - `create`: if `True` and `nick_or_jid` is a JID, then a new
                user object will be created if there is no such user in the room.
          :Types:
              - `nick_or_jid`: `unicode` or `JID`
              - `create`: `bool`
  
          :return: the named user or `None`
          :returntype: `MucRoomUser`