def unicode_is_ascii ( u_string ) : assert isinstance ( u_string , str ) try : u_string . encode ( 'ascii' ) return True except UnicodeEncodeError : return False
testing whether a string is ascii in python
Determine if unicode string only contains ASCII characters .
def unicode_is_ascii(u_string):
    """Determine if unicode string only contains ASCII characters.

    :param str u_string: unicode string to check. Must be unicode
        and not Python 2 `str`.
    :rtype: bool
    """
    assert isinstance(u_string, str)
    try:
        u_string.encode('ascii')
        return True
    except UnicodeEncodeError:
        return False