def get_length(self, y):
        """Get true length of y.

        Args:
            y (list): padded list.

        Returns:
            lens: true length of y.

        Examples:
            >>> y = [[1, 0, 0], [1, 1, 0], [1, 1, 1]]
            >>> self.get_length(y)
            [1, 2, 3]
        """
        lens = [self.find_pad_index(row) for row in y]
        return lens
Get true length of y.

        Args:
            y (list): padded list.

        Returns:
            lens: true length of y.

        Examples:
            >>> y = [[1, 0, 0], [1, 1, 0], [1, 1, 1]]
            >>> self.get_length(y)
            [1, 2, 3]