string.py 文件源码

def _apply(self, value):
        value = self._filter(value, Type(text_type)) # type: Text

        if self._has_errors:
            return None

        try:
            # :see: http://stackoverflow.com/a/6921760
            return self.decoder(value, object_pairs_hook=OrderedDict)
        except ValueError:
            return self._invalid_value(value, self.CODE_INVALID, exc_info=True)