# File lib/rhc/helpers.rb, line 231
    def certificate_file(file)
      file && OpenSSL::X509::Certificate.new(IO.read(File.expand_path(file)))
    rescue => e
      debug e
      raise OptionParser::InvalidOption.new(nil, "The certificate '#{file}' cannot be loaded: #{e.message} (#{e.class})")
    end