# How come abs(x) works?

Hello,

I notice that `abs`

is a Python built-in function, but it also works symbolically:

```
sage: abs(x)
abs(x)
sage: bool(abs(x) == abs_symbolic(x))
True
sage: preparse('abs(x)')
'abs(x)'
```

What's going on here? Obviously the Python function should not accept a Sage type.