From 95b7cfea8de1d4f65df05eae871aae6719ed2447 Mon Sep 17 00:00:00 2001
From: Acme Contributor <noreply@google.com>
Date: Wed, 2 Aug 2023 07:10:01 -0700
Subject: [PATCH] Internal change.

PiperOrigin-RevId: 553134800
Change-Id: I9880dbd0ee617d37bb884cedabe591f44120e58b
---
 acme/adders/reverb/structured.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/acme/adders/reverb/structured.py b/acme/adders/reverb/structured.py
index b99f171589..de2b712057 100644
--- a/acme/adders/reverb/structured.py
+++ b/acme/adders/reverb/structured.py
@@ -153,7 +153,7 @@ def add(self,
           extras: types.NestedArray = ()):
     """Record an action and the following timestep."""
 
-    if not self._writer.step_is_open:
+    if self._writer is None or not self._writer.step_is_open:
       raise ValueError('adder.add_first must be called before adder.add.')
 
     # Add the timestep to the buffer.