Unless you feel like struggling with the 2.7's custom calltip calculation code for possibly little or no gain, please close this as wont' fix. See #20122, especially msg208454 and point 3. f6f2d9d04cd0 made this change to improve the calltip for *x and **y from always completely wrong to usually right:
-                items.append("...")
+                items.append("*args")
             if fob.func_code.co_flags & 0x8:
-                items.append("***")
+                items.append("**kwds")

This issue was fixed in 3.x, which does not have old-style classes to contend with.