def find_in_line(line):  # type: (str) -> Optional[str]
    """
    Find a version in a line.
    :param line:
    :return:
    """
    if not line:
        return None

    for method in [find_by_ast, find_version_by_string_lib, find_version_by_regex]:
        by = method(line)
        by = validate_string(by)
        if by:
            return by
    return None
Find a version in a line.
    :param line:
    :return: