Joins a given name with an extension. If the extension doesn't have a '.'
    it will add it for you

def join_ext(name, extension):
    """
    Joins a given name with an extension. If the extension doesn't have a '.'
    it will add it for you
    """
    if extension[0] == EXT:
        ret = name + extension
    else:
        ret = name + EXT + extension
    return ret