code: def run(self) -> Generator[Tuple[int, int, str, type], None, None]:
          
          if self.filename != STDIN:
              buffer = StringIO()
              options = _Options(aggressive=self.options.eradicate_aggressive)
              fix_file(self.filename, options, buffer)
              traceback = buffer.getvalue()
  
              if traceback:
                  yield 1, 0, self._error(traceback), type(self)
docs: Runs the checker.
  
          ``fix_file()`` only mutates the buffer object.
          It is the only way to find out if some error happened.