def _error_is_decreasing(self, last_error):
        """True if current error is less than last_error."""
        current_error = self._compute_error()
        is_decreasing = current_error < last_error
        return is_decreasing, current_error
def _error_is_decreasing ( self , last_error ) : current_error = self . _compute_error ( ) is_decreasing = current_error < last_error return is_decreasing , current_error
True if current error is less than last_error.