### Pass a list of variable names as parameter to a polynomial ring

I am trying to write a function that compute a vector space basis $B$ for the quotient ring $k[x_1,\dots,x_n]/I$. I want to make the list of variables as the input parameter.

I tried this:

```
var("x,y")
Vlist=[x,y]
P.<Vlist>=PolynomialRing(QQ,order='degrevlex')
f=x^2+y^3
f.lm()
```

It gave me error message. I also tried

```
Vlist=['x,y']
```

or

```
Vlist=["x,y"]
```

None of them works.
I know that

```
P.<x,y>=PolynomialRing(QQ,order='degrevlex')
f=x^2+y^3
f.lm()
```

works. So I can just type this before I run my function. But is there a way that I can make this as input of the function?