Fix linting.

typings/docplex/mp/basic.pyi

@@ -0,0 +1,8 @@
+from __future__ import annotations
+
+from typing import Literal
+
+from docplex.mp.operand import Operand
+
+class Expr(Operand):
+    def __pow__(self, power: Literal[0, 1, 2]) -> Expr: ...