diff --git a/doc/conf.py b/doc/conf.py
index e79134cc3d7..ced3a6723fc 100644
--- a/doc/conf.py
+++ b/doc/conf.py
@@ -26,7 +26,9 @@ html_baseurl = os.environ.get("READTHEDOCS_CANONICAL_URL", "")
 
 # Tell Jinja2 templates the build is running on Read the Docs
 if os.environ.get("READTHEDOCS", "") == "True":
-    html_context["READTHEDOCS"] = True
+    html_context = {
+        'READTHEDOCS' : True,
+    }
 
 # If extensions (or modules to document with autodoc) are in another directory,
 # add these directories to sys.path here. If the directory is relative to the