code: def has_control_chars(i):
          
          if not hasattr(i, 'type_'):
              return False
  
          if i.type_ != Type.string:
              return False
  
          if i.token in ('VAR', 'PARAMDECL'):
              return True  # We don't know what an alphanumeric variable will hold
  
          if i.token == 'STRING':
              for c in i.value:
                  if 15 < ord(c) < 22:  # is it an attr char?
                      return True
              return False
  
          for j in i.children:
              if Translator.has_control_chars(j):
                  return True
  
          return False
docs: Returns true if the passed token is an unknown string
          or a constant string having control chars (inverse, etc