# flatten
Flatten nested lists into a single list.
## Syntax
[flatten $list]
## Examples
[flatten @{ @{ 1 2 } @{ 3 4 } }] # @{ 1 2 3 4 }
[flatten @{ 1 @{ 2 @{ 3 } } }] # @{ 1 2 3 }
## Returns
Single-level list.
## See Also
`unique`, `zip`, `append`