class_docstr: ngram op test
code: def setUp(self):
      super().setUp()
      self.testcase = [
          [0, 0, 0, 0],
          [223, 0, 0, 0],
          [0, 8, 0, 0],
          [4, 8, 0, 0],
          [0, 0, 10, 0],
          [2, 5, 3, 0],
          [7, 2, 1, 24],
      ]
  
file_path: delta/core/ops/kernels/ngram_op_test.py
imports: import delta.compat
  from absl import logging
  from delta.layers.ops import py_x_ops
label_desc: Use image node_id 1 for calling the NGramOpsTest obj's underlying member method code with example usage: obj.setUp() without return types