pool.py 文件源码

def _do_get(self):
        if self._checked_out:
            if self._checkout_traceback:
                suffix = ' at:\n%s' % ''.join(
                    chop_traceback(self._checkout_traceback))
            else:
                suffix = ''
            raise AssertionError("connection is already checked out" + suffix)

        if not self._conn:
            self._conn = self._create_connection()

        self._checked_out = True
        if self._store_traceback:
            self._checkout_traceback = traceback.format_stack()
        return self._conn