# Monomial with power modulo n

I need to implement the following formal structure $$ax^\gamma, \gamma \in \mathbb{Z}/n\mathbb{Z}, a \in \mathbb{R}$$ and $x$ is a formal variable.

I tried

```
ZZ6 = Integers(6)
x = var('x')
x^ZZ6(9) + x^ZZ6(11)
```

And get value `x^8`

, whereas I need `x^ZZ6(8)`

.

How can I do this in sage?