Determine whether the string looks like an egg_info.

    :param s: The string to parse. E.g. foo-2.1

def _contains_egg_info(
        s, _egg_info_re=re.compile(r'([a-z0-9_.]+)-([a-z0-9_.!+-]+)', re.I)):
    """Determine whether the string looks like an egg_info.

    :param s: The string to parse. E.g. foo-2.1
    """
    return bool(_egg_info_re.search(s))