From e4d0990857bb813a55e9f95de6c77c1026460006 Mon Sep 17 00:00:00 2001
From: Ines Montani <ines@ines.io>
Date: Fri, 14 Aug 2020 14:58:48 +0200
Subject: [PATCH] Only receive from listener if listener exists

---
 spacy/pipeline/tok2vec.py | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/spacy/pipeline/tok2vec.py b/spacy/pipeline/tok2vec.py
index 44cd457e4..f2d138cf7 100644
--- a/spacy/pipeline/tok2vec.py
+++ b/spacy/pipeline/tok2vec.py
@@ -193,7 +193,8 @@ class Tok2Vec(Pipe):
         batch_id = Tok2VecListener.get_batch_id(docs)
         for listener in self.listeners[:-1]:
             listener.receive(batch_id, tokvecs, accumulate_gradient)
-        self.listeners[-1].receive(batch_id, tokvecs, backprop)
+        if self.listeners:
+            self.listeners[-1].receive(batch_id, tokvecs, backprop)
         if set_annotations:
             self.set_annotations(docs, tokvecs)
         return losses