# Limit with variables from array

The following code:

```
x = [var(f'x{i}') for i in range(3)]
f = sum(x)
f.limit(x[1]=1)
```

gives an error:

SyntaxError: expression cannot contain assignment, perhaps you meant "=="?

If I replace `x[1]=1`

with `x[1]==1`

, I get

ValueError: call the limit function like this, e.g. limit(expr, x=2).

and we go in circles. How to proceed?

ADDED. This issue has been reported at https://github.com/sagemath/sage/issu...