code: def _rollaxis_right(A, num_rolls):
      
      assert num_rolls > 0
      rank = tf.rank(A)
      perm = tf.concat([rank - num_rolls + tf.range(num_rolls), tf.range(rank - num_rolls)], 0)
      return tf.transpose(A, perm)
docs: Roll the tensor `A` forward `num_rolls` times