code: func (q *Query) endCall() *Call {
  	elem := q.callStack[len(q.callStack)-1]
  	q.callStack[len(q.callStack)-1] = nil
  	q.callStack = q.callStack[:len(q.callStack)-1]
  	return elem.call
  }
docs: // endCall removes the last element from the call stack and returns the call.