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: visitor.rb
    path of file: ./repos/graphql-ruby/lib/graphql/language
    
    the code of the file until where you have to start completion: # frozen_string_literal: true
module GraphQL
  module Language
    # Depth-first traversal through 
    
      def on_operation_definition_children(new_node)
        new_node.variables.each do |arg_node|
          new_child_and_node = on_variable_definition_with_modifications(arg_node, new_node)
          # Reassign `node` in case the child hook makes a modification
          if new_child_and_node.is_a?(Array)
            new_node = new_child_and_node[1]
          end
        end