code: def lib2to3_parse(src_txt):
      
      grammar = pygram.python_grammar_no_print_statement
      drv = driver.Driver(grammar, pytree.convert)
      if src_txt[-1] != '\n':
          nl = '\r\n' if '\r\n' in src_txt[:1024] else '\n'
          src_txt += nl
      try:
          result = drv.parse_string(src_txt, True)
      except ParseError as pe:
          lineno, column = pe.context[1]
          lines = src_txt.splitlines()
          try:
              faulty_line = lines[lineno - 1]
          except IndexError:
              faulty_line = "<line number missing in source>"
          raise ValueError(f"Cannot parse: {lineno}:{column}: {faulty_line}") from None
  
      if isinstance(result, Leaf):
          result = Node(syms.file_input, [result])
  
      return result
docs: Given a string with source, return the lib2to3 Node.