You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: helper.rb
    path of file: ./repos/steep/lib/steep/ast/types
    
    the code of the file until where you have to start completion: module Steep
  module AST
    module Types
      module Helper
        module ChildrenLevel
          def level_of_children(children)
            levels = children.map(&:level)
 
    
          def level_of_children(children)
            levels = children.map(&:level)
            children.map(&:level).sort {|a, b| (b.size <=> a.size) || 0 }.inject() do |a, b|
              a.zip(b).map do |x, y|
                if x && y
                  x + y
                else
                  x || y || raise
                end
              end
            end || []
          end