parameters: (self, node, reason=None)
docstring: Warn the user that a given chunk of code is not valid Python 3,
          but that it cannot be converted automatically.
  
          First argument is the top-level node for the code in question.
          Optional second argument is why it can't be converted.
docstring_summary: Warn the user that a given chunk of code is not valid Python 3,
          but that it cannot be converted automatically.
docstring_tokens: Warn the user that a given chunk of code is not valid Python 3 but that it cannot be converted automatically .
function: def cannot_convert(self, node, reason=None):
          """Warn the user that a given chunk of code is not valid Python 3,
          but that it cannot be converted automatically.
  
          First argument is the top-level node for the code in question.
          Optional second argument is why it can't be converted.
          """
          lineno = node.get_lineno()
          for_output = node.clone()
          for_output.prefix = ""
          msg = "Line %d: could not convert: %s"
          self.log_message(msg % (lineno, for_output))
          if reason:
              self.log_message(reason)
function_tokens: def cannot_convert ( self , node , reason = None ) : lineno = node . get_lineno ( ) for_output = node . clone ( ) for_output . prefix = "" msg = "Line %d: could not convert: %s" self . log_message ( msg % ( lineno , for_output ) ) if reason : self . log_message ( reason )