# LibTmux::FilterExpr#not

- **Module:** LibTmux
- **Package:** libtmux
- **Language:** Ruby
- **Kind:** method
- **Source:** https://github.com/libtmux/libtmux-ruby/blob/d8ce4bbee0ca7748a81929f81f7d8d07f8c51267/gems/libtmux/lib/libtmux/criteria.rb#L91
- **Page:** https://libtmux.org/en/ruby/v0.1.0.alpha.3/reference/libtmux-filterexpr-not/

```
def not: () -> ::LibTmux::FilterExpr
```

Behavior: Criteria.

Behavior contract: Criteria.