code: def testNGramsWithSpaceSeparator(self):
      with tf.compat.v1.Graph().as_default():
          string_tensor = tf.constant(
              ["One was Johnny", "Two was a rat"]
          )
          tokenized_tensor = tf.compat.v1.strings.split(
              string_tensor, sep=" "
          )
          output_tensor = mappers.ngrams(
              tokens=tokenized_tensor, ngram_range=(1, 2), separator=" "
          )
          with tf.compat.v1.Session():
              output = output_tensor.eval()
              self.assertAllEqual(
                  output.indices,
                  [
                      [0, 0],
                      [0, 1],
                      [0, 2],
                      [0, 3],
                      [0, 4],
                      [1, 0],
                      [1, 1],
                      [1, 2],
                      [1, 3],
                      [1, 4],
                      [1, 5],
                      [1, 6],
                  ],
              )
              self.assertAllEqual(
                  output.values,
                  [
                      b"One",
                      b"One was",
                      b"was",
                      b"was Johnny",
                      b"Johnny",
                      b"Two",
                      b"Two was",
                      b"was",
                      b"was a",
                      b"a",
                      b"a rat",
                      b"rat",
                  ],
              )
              self.assertAllEqual(output.dense_shape, [2, 7])
  
imports: import numpy
  import tensorflow
  from tensorflow_transform import mappers
  from tensorflow_transform import test_case
label_desc: Use image node_id 7 for calling the MappersTest obj's underlying member method code with example usage: obj.testNGramsWithSpaceSeparator() without return types