class_docstr: vocab op test 
class_docstr_tok: ["vocab","op","test"]
docstr: tset vocab token to id
docstr_tok: ["tset","vocab","token","to","id"]
code: def test_vocab_token_to_id(self):
      """tset vocab token to id"""
      with self.cached_session(use_gpu=False, force_gpu=False):
          vocab = [
              "<s>",
              "</s>",
              "<unk>",
              "<epsilon>",
              "a",
              "b c d e",
              "øut",
              "über",
              "♣",
              "愤青",
              "←",
          ]
          self.assertEqual(
              0, py_x_ops.vocab_token_to_id("<s>", vocab=vocab).eval()
          )
          self.assertEqual(
              4, py_x_ops.vocab_token_to_id("a", vocab=vocab).eval()
          )
          self.assertAllEqual(
              [5, 8],
              py_x_ops.vocab_token_to_id(
                  ["b c d e", "♣"], vocab=vocab
              ).eval(),
          )
          self.assertEqual(
              2,
              py_x_ops.vocab_token_to_id("unknown", vocab=vocab).eval(),
          )
  
file_path: delta/core/ops/kernels/simple_vocab_op_test.py
imports: import delta.compat
  from delta.layers.ops import py_x_ops
label_desc: Use image node_id 3 for calling the VocabOpsTest obj's underlying member method code with example usage: obj.test_vocab_token_to_id() without return types