### p-adic power series

Hello,

I am new to Sage and I want to to do some math on p-adic power series. I want to
define such a power series but I did not succeeded. The last line of the
following code rises an exception:

```
p = 2
q = 4
K = Qp(p)
L.<omega> = Qq(q)
O_L = L.integer_ring()
R.<X> = PowerSeriesRing(O_L)
pi = L.uniformizer()
q = L.residue_class_degree()
f(X) = X^q + pi*X
```

**TypeError: unsupported operand parent(s) for '*': '2-adic Field with capped
relative precision 20' and 'Symbolic Ring'**

Can someone help me, please? Thanks for your time!

Bye
Lars