### Check that variable is integer

Dear Sage,

I define the following variable

```
sage: a = var('a')
sage: assume(a, 'integer')
```

How do I check that is variable is an integer? The following doese not seem to work in sage 5.2.

```
sage: a in ZZ
False
sage: 2 in ZZ
True
sage: assumptions()
[a is integer]
```

How should I check the assumption that a is an integer?

Best,
Noud