Get at least some usages stuff right.

jedi/parser/representation.py

@@ -1470,7 +1470,8 @@ class Param(Base):
         return self.get_parent_until(IsScope)
 
     def get_code(self):
-        return self.tfpdef.get_code()
+        df = '' if self.default is None else '=' + self.default.get_code()
+        return self.tfpdef.get_code() + df
 
     def __init__old(self):
         kwargs.pop('names_are_set_vars', None)