<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def _compute(self, feed_dict, shard):
 """ Call the tensorflow compute """


        try:
            descriptor, enq = self._tfrun(self._tf_expr[shard], feed_dict=feed_dict)
            self._inputs_waiting.decrement(shard)

        except Exception as e:
            montblanc.log.exception("Compute Exception")
            raise