def run(self) -> Generator[Tuple[int, int, str, type], None, None]:
if self.filename != STDIN:<EOL><INDENT>buffer = StringIO()<EOL>options = _Options(aggressive=self.options.eradicate_aggressive)<EOL>fix_file(self.filename, options, buffer)<EOL>traceback = buffer.getvalue()<EOL>if traceback:<EOL><INDENT>yield <NUM_LIT:1>, <NUM_LIT:0>, self._error(traceback), type(self)<EOL><DEDENT><DEDENT>
Runs the checker.

``fix_file()`` only mutates the buffer object.
It is the only way to find out if some error happened.