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: prompt.rb
    path of file: ./repos/boxcars/lib/boxcars
    
    the code of the file until where you have to start completion: # frozen_string_literal: true

module Boxcars
  # used by Boxcars that have
    
    def format(inputs)
      @template % inputs
    rescue ::KeyError => e
      first_line = e.message.to_s.split("\n").first
      Boxcars.error "Missing prompt input key: #{first_line}"
      raise KeyError, "Prompt format error: #{first_line}"
    end