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: maybe.rb
    path of file: ./repos/dry-types/lib/dry/types/extensions
    
    the code of the file until where you have to start completion: # frozen_string_literal: true

require 
    
      def call_safe(input = Undefined)
        case input
        when ::Dry::Monads::Maybe
          input
        when Undefined
          None()
        else
          Maybe(type.call_safe(input) { |output = input| return yield(output) })
        end