# Using timeit in an interact without string formatting

I wanted the following to work, but it didn't. Anyone have an idea how to make it do so?

```
def T(n):
top = ceil(math.sqrt(n))
print top
@interact
def _(n=6739815371):
T(n)
timeit('T(n)')
```

Instead I had to do

```
def T(n):
top = ceil(math.sqrt(n))
print top
@interact
def _(n=6739815371):
T(n)
timeit('T(%s)'%n)
```

But I feel like the first thing did indeed work in the past (though I tried it with a Sage from 2010 to no avail).

I guess in some sense this is a silly question - `'T(n)'`

is a string, pure and simple. At the same time, in the command line

```
sage: def T(n):
....: top = ceil(math.sqrt(n))
....: print top
....:
sage: n=6739815371
sage: timeit('T(n)')
625 loops, best of 3: 5.96 µs per loop
```

and `'T(n)'`

is a string there too. So what is different about `interact`

that this doesn't work (in Sage or the cell server)?