Fix

Author: stsewd

readthedocs/doc_builder/base.py

@@ -53,7 +53,7 @@ def __init__(self, build_env, python_env, force=False):
 
     def get_final_doctype(self):
         """Some builders may have a different doctype at build time."""
-        self.config.doctype
+        return self.config.doctype
 
     def force(self, **__):
         """An optional step to force a build even when nothing has changed."""