Modified __add__ method in tuple class (#3252)

Modified __add__ method in tuple class to allow it to accept tuples with different generic parameter types. This allows, for example:
a = (1, )
b = a + (2.4, )

Author: erictraut

stdlib/2/__builtin__.pyi

@@ -867,7 +867,10 @@ class tuple(Sequence[_T_co], Generic[_T_co]):
     def __le__(self, x: Tuple[_T_co, ...]) -> bool: ...
     def __gt__(self, x: Tuple[_T_co, ...]) -> bool: ...
     def __ge__(self, x: Tuple[_T_co, ...]) -> bool: ...
+    @overload
     def __add__(self, x: Tuple[_T_co, ...]) -> Tuple[_T_co, ...]: ...
+    @overload
+    def __add__(self, x: tuple) -> tuple: ...
     def __mul__(self, n: int) -> Tuple[_T_co, ...]: ...
     def __rmul__(self, n: int) -> Tuple[_T_co, ...]: ...
     def count(self, x: Any) -> int: ...

stdlib/2and3/builtins.pyi

@@ -867,7 +867,10 @@ class tuple(Sequence[_T_co], Generic[_T_co]):
     def __le__(self, x: Tuple[_T_co, ...]) -> bool: ...
     def __gt__(self, x: Tuple[_T_co, ...]) -> bool: ...
     def __ge__(self, x: Tuple[_T_co, ...]) -> bool: ...
+    @overload
     def __add__(self, x: Tuple[_T_co, ...]) -> Tuple[_T_co, ...]: ...
+    @overload
+    def __add__(self, x: tuple) -> tuple: ...
     def __mul__(self, n: int) -> Tuple[_T_co, ...]: ...
     def __rmul__(self, n: int) -> Tuple[_T_co, ...]: ...
     def count(self, x: Any) -> int: ...