We use 2 newlines between top-level definitions in our codebase. eg.

f :: Int -> Int -> Int
f x y = square x + square y
  where
    square a = a * a


g :: Int -> Int
g z = f z z

as opposed to (single newline):

f :: Int -> Int -> Int
f x y = square x + square y
  where
    square a = a * a

g :: Int -> Int
g z = f z z

It would be great if fourmolu had a configurable number of newlines between top-level definitions, such that we could set it to 2 instead of 1!