# LibTmux::FilterExpr#not

- **Module:** LibTmux
- **Package:** libtmux
- **Language:** Ruby
- **Kind:** method
- **Source:** https://github.com/libtmux/libtmux-ruby/blob/46474e8a2f03e39fc2b0ff73b6a841777b79c4d2/gems/libtmux/lib/libtmux/criteria.rb#L91
- **Page:** https://libtmux.org/en/ruby/v0.1.2/reference/libtmux-filterexpr-not/

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

Behavior: Criteria.

Behavior contract: Criteria.