def coerce(cls, string):
        """Create a :class:`Requirement` object from a given package spec."""
        match = re.match(cls.spec_regex, string)
        if not match:
            raise InvalidRequirementSpecError("could not parse requirement")
        package = match.group(1)
        if all(match.group(2, 3)):
            version = "".join(match.group(2, 3))
        else:
            version = None
        return cls(package, version)
def find_first_remote_branch(remotes: Sequence['Remote'], branch_name: str) -> 'RemoteReference':
    """Find the remote branch matching the name of the given branch or raise InvalidGitRepositoryError"""
    for remote in remotes:
        try:
            return remote.refs[branch_name]
        except IndexError:
            continue
        # END exception handling
    # END for remote
    raise InvalidGitRepositoryError("Didn't find remote branch '%r' in any of the given remotes" % branch_name)