def get_best_encoding ( stream ) : rv = getattr ( stream , 'encoding' , None ) or sys . getdefaultencoding ( ) if is_ascii_encoding ( rv ) : return 'utf-8' return rv
python file encoding judge
Returns the default stream encoding if not found .
def get_best_encoding(stream):
    """Returns the default stream encoding if not found."""
    rv = getattr(stream, 'encoding', None) or sys.getdefaultencoding()
    if is_ascii_encoding(rv):
        return 'utf-8'
    return rv