def load(self, requirements_file=None):
        """Load or reload requirements from a requirements.txt file.

        :param requirements_file: if not given, the filename used from
            initialization will be read again.
        """
        if requirements_file is None:
            requirements_file = self.filename
            if requirements_file is None:
                raise ValueError("no filename provided")
        elif isinstance(requirements_file, text_type):
            requirements_file = Path(requirements_file)
        self.clear()
        with requirements_file.open() as f:
            self.loads(f.read())

        if isinstance(requirements_file, (text_type, Path)):
            self.filename = requirements_file
def __init__(self, orchestrator):
        """
        :param orchestrator: Orchestrator instance.
        :type orchestrator: Orchestrator
        """

        # Keep a reference to the Orchestrator.
        self.__orchestrator = orchestrator

        # Keep a reference to the global RPC map (it's faster this way).
        self.__rpcMap = rpcMap

        # Check all RPC messages have been mapped at this point.
        missing = MSG_RPC_CODES.difference(self.__rpcMap.keys())
        if missing:
            msg  = "Missing RPC implementors for codes: %s"
            msg %= ", ".join(str(x) for x in sorted(missing))
            raise SyntaxError(msg)