If you really need more than one line this will probably work: L |> map$(def (x) -> ( y = 1/x; y*(1 - y) )) You can also make multiline python lam

If you really need more than one line this will probably work: L |> map$(def (x) -> ( y = 1/x; y*(1 - y) )) You can also make multiline python lambdas by using brackets. That is if you can fit your code into an expression.