Fix typecheck

src/pystencils/backend/reduction_op_mapping.py

@@ -15,18 +15,17 @@ def reduction_op_to_expr(op: ReductionOp, op1, op2) -> PsExpression:
     if op in _available_operator_interface:
         match op:
             case ReductionOp.Add:
-                operator = PsAdd
+                return PsAdd(op1, op2)
             case ReductionOp.Sub:
-                operator = PsSub
+                return PsSub(op1, op2)
             case ReductionOp.Mul:
-                operator = PsMul
+                return PsMul(op1, op2)
             case ReductionOp.Div:
-                operator = PsDiv
+                return PsDiv(op1, op2)
             case _:
                 raise FreezeError(
                     f"Found unsupported operation type for reduction assignments: {op}."
                 )
-        return operator(op1, op2)
     else:
         match op:
             case ReductionOp.Min: