module Steep::AST::Types::Helper::ChildrenLevel

def level_of_children(children)
  children.map(&:level).sort {|a, b| b.size <=> a.size }.inject() do |a, b|
    a.zip(b).map do |(x, y)|
      if x && y
        x + y
      else
        x || y
      end
    end
  end || []
end