import tensorflow as tf

    # Make a matrix where each row contains [0, 1, ..., max_sequence_len]
    r = tf.range(0, max_sequence_len, 1)
    range_row = tf.expand_dims(r, 0)
    range_tiled = tf.tile(range_row, [batch_size, 1])

    # Use the logical operations to create a mask
