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 _check_version(version, filename):
    major, minor = version.split('.')

    try:
        major = int(major)
    except ValueError as e:
        raise TransactionReplayError(
            filename,
            _('Invalid major version "{major}", number expected.').format(major=major)
        )

    try:
        int(minor)  # minor is unused, just check it's a number
    except ValueError as e:
        raise TransactionReplayError(
            filename,
            _('Invalid minor version "{minor}", number expected.').format(minor=minor)
        )

    if major != VERSION_MAJOR:
        raise IncompatibleTransactionVersionError(
            filename,
            _('Incompatible major version "{major}", supported major version is "{major_supp}".')
                .format(major=major, major_supp=VERSION_MAJOR)
        )