checks if an object (like a file-like object) is a tty.

def ob_is_tty(ob):
    """ checks if an object (like a file-like object) is a tty.  """
    fileno = get_fileno(ob)
    is_tty = False
    if fileno:
        is_tty = os.isatty(fileno)
    return is_tty