* Introducing `tf.types.experimental.FunctionType` as the comprehensive representation of the signature of `tf.function` callables. It can be accessed through the `function_type` property of `tf.function`s and `ConcreteFunction`s. See the `tf.types.experimental.FunctionType` documentation for more details.

      return getArgsMutable();
    }

    // Returns the callee of this operation.
    CallInterfaceCallable getCallableForCallee() { return getFAttr(); }
    // Sets the callee from the callable.
    void setCalleeFromCallable(CallInterfaceCallable callee);

    // returns the callee of this operation.
    func::FuncOp func() {