code: def test_forward_call_en_us(self):
      input_text = (
          "Hello NVIDIA'S airport's Jones's airports worlds Kitty!"
      )
  
      g2p_upper = self._create_g2p(
          locale="en-US", grapheme_case=GRAPHEME_CASE_UPPER
      )
      expected_output_upper = [
          char
          for char in "həˈɫoʊ ɛnˈvɪdiəz ˈɛɹˌpɔɹts ˈdʒoʊnzɪz ˈɛɹˌpɔɹts ˈwɝɫdz KITTY!"
      ]
  
      g2p_lower = self._create_g2p(
          locale="en-US",
          grapheme_case=GRAPHEME_CASE_LOWER,
          grapheme_prefix=self.GRAPHEME_PREFIX,
          apply_to_oov_word=None,
      )
      expected_output_lower = (
          [
              char
              for char in "həˈɫoʊ ɛnˈvɪdiəz ˈɛɹˌpɔɹts ˈdʒoʊnzɪz ˈɛɹˌpɔɹts ˈwɝɫdz"
          ]
          + [" "]
          + [f"{self.GRAPHEME_PREFIX}{char}" for char in "kitty"]
          + ["!"]
      )
  
      g2p_mixed = self._create_g2p(
          locale="en-US",
          grapheme_case=GRAPHEME_CASE_MIXED,
          grapheme_prefix=self.GRAPHEME_PREFIX,
          apply_to_oov_word=None,
      )
      expected_output_mixed = (
          [
              char
              for char in "həˈɫoʊ ɛnˈvɪdiəz ˈɛɹˌpɔɹts ˈdʒoʊnzɪz ˈɛɹˌpɔɹts ˈwɝɫdz"
          ]
          + [" "]
          + [f"{self.GRAPHEME_PREFIX}{char}" for char in "kitty"]
          + ["!"]
      )
  
      for g2p, expected_output in zip(
          [g2p_upper, g2p_lower, g2p_mixed],
          [
              expected_output_upper,
              expected_output_lower,
              expected_output_mixed,
          ],
      ):
          phonemes = g2p(input_text)
          assert phonemes == expected_output
  
imports: import os
  import unicodedata
  import pytest
  from nemo.collections.tts.g2p.models.i18n_ipa import IpaG2p
  from nemo.collections.tts.g2p.utils import GRAPHEME_CASE_LOWER, GRAPHEME_CASE_MIXED, GRAPHEME_CASE_UPPER
label_desc: Use image node_id 18 for calling the TestIpaG2p obj's underlying member method code with example usage: obj.test_forward_call_en_us() without return types