exceptions.py 文件源码

def format_exc(self, limit=None):
        """
        This is like exception.print_exc(limit) but returns a string instead
        of printing to a file.
        """
        result = ["Traceback (most recent call last):\n"]

        tb_list = self._traceback

        if limit is not None:
            tb_list = tb_list[-limit:]

        result.extend(traceback.format_list(tb_list))

        if self.cause is not None:
            result.extend(traceback.format_exception_only(self.cause.__class__,
                                                          self.cause))
            return result
        else:
            return result