### Assume expression to be noninteger

Hello!
How to assume expression to be an integer? I try to do some symbolic integration while Sage asks to provide additional info about expression. MWE:

```
var('x a b')
assume(b > 0)
f = (exp((x-a)/b) + 1)**(-1)
(f*f).integrate(x, 0, oo)
```

gives:

ValueError: Computation failed since Maxima requested additional constraints; using the 'assume' command before evaluation *may* help (example of legal syntax is 'assume((2*a)/b>0)', see *`assume?`

for more details)
Is (2a)/b an integer?

How to assume that `(2*a)/b`

is an arbitrary positive real number? Straightforward `assume((2*a)/b, 'noninteger')`

gives:

TypeError: self (=2*a/b) must be a relational expression

Thanks!