code: def test_unreachable_implicit1(self) -> None:
      source = """
          start: NAME | invalid_input
          invalid_input: NUMBER { None }
          """
      grammar = parse_string(source, GrammarParser)
      out = io.StringIO()
      genr = PythonParserGenerator(
          grammar, out, unreachable_formatting="This is a test"
      )
      genr.generate("<string>")
      self.assertIn("This is a test", out.getvalue())
  
imports: import ast
  import difflib
  import io
  import textwrap
  import unittest
  from test import test_tools
  from typing import Dict, Any
  from tokenize import TokenInfo, NAME, NEWLINE, NUMBER, OP
label_desc: Use image node_id 37 for calling the TestPegen obj's underlying member method code with example usage: obj.test_unreachable_implicit1() without return types