@staticmethod
def candidate_urls(bzr_branch):
    """Iterate through related URLs that might be Launchpad URLs.

        :param bzr_branch: A Bazaar branch to find URLs from.
        :return: a generator of URL strings.
        """
    url = bzr_branch.get_public_branch()
    if url is not None:
        yield url
    url = bzr_branch.get_push_location()
    if url is not None:
        yield url
    url = bzr_branch.get_parent()
    if url is not None:
        yield url
    yield bzr_branch.base
