code: def validateMasterArgument(self, master_arg):
          
          if master_arg[:5] == "http:":
              raise usage.UsageError("<master> is not a URL - do not use URL")
  
          if ":" not in master_arg:
              master = master_arg
              port = 9989
          else:
              master, port = master_arg.split(":")
  
          if not master:
              raise usage.UsageError("invalid <master> argument '{}'".format(
                                     master_arg))
          try:
              port = int(port)
          except ValueError:
              raise usage.UsageError("invalid master port '{}', "
                                     "needs to be a number".format(port))
  
          return master, port
docs: Parse the <master> argument.
  
          @param master_arg: the <master> argument to parse
  
          @return: tuple of master's host and port
          @raise UsageError: on errors parsing the argument