An HTTPResponse is, by its nature, readable.
diff --git a/Lib/http/client.py b/Lib/http/client.py
index 4885f5a..cef942f 100644
--- a/Lib/http/client.py
+++ b/Lib/http/client.py
@@ -469,6 +469,9 @@
     def flush(self):
         self.fp.flush()
 
+    def readable(self):
+        return True
+
     # End of "raw stream" methods
 
     def isclosed(self):