def _parallel_compare_helper ( class_obj , pairs , x , x_link = None ) : return class_obj . _compute ( pairs , x , x_link )
python can not pickle local objects
Internal function to overcome pickling problem in python2 .
def _parallel_compare_helper(class_obj, pairs, x, x_link=None):
    """Internal function to overcome pickling problem in python2."""
    return class_obj._compute(pairs, x, x_link)