bpo-40462: fix variable and function names (GH-19832)



Automerge-Triggered-By: @vstinner
diff --git a/Lib/test/mock_socket.py b/Lib/test/mock_socket.py
index b28c473..cda4db2 100644
--- a/Lib/test/mock_socket.py
+++ b/Lib/test/mock_socket.py
@@ -91,7 +91,7 @@
         handle = MockFile(self.lines)
         return handle
 
-    def sendall(self, buffer, flags=None):
+    def sendall(self, data, flags=None):
         self.last = data
         self.output.append(data)
         return len(data)