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: output_builder.rb
    path of file: ./repos/grape-entity/lib/grape_entity/exposure/nesting_exposure
    
    the code of the file until where you have to start completion: # frozen_string_literal: true

module Grape
  class Entity
    module Exposure
      class NestingExposure
        
    
          def output
            if @output_collection.empty?
              output = @output_hash
            else
              output = @output_collection
              output << @output_hash unless @output_hash.empty?
              output.flatten!
            end