def remove(self, elem):
        """Remove a requirement.

        :param elem: a string or :class:`Requirement` instance.
        """
        if isinstance(elem, text_type):
            for requirement in self:
                if requirement.package == elem:
                    return super(Requirements, self).remove(requirement)
        return super(Requirements, self).remove(elem)
def _load_from_file(self, fn):
        self._filename = fn
        with open(fn, "r") as f:
            try:
                replay_data = json.load(f)
            except json.decoder.JSONDecodeError as e:
                raise TransactionReplayError(fn, str(e) + ".")

        try:
            self._load_from_data(replay_data)
        except TransactionError as e:
            raise TransactionReplayError(fn, e)