def verify
      missing = packages.reject(&:verify)

      if missing.any?
        raise Errors::MissingPackages.new(missing)
      end
    end
def verify
      missing = packages.reject(&:verify)

      if missing.any?
        raise Errors::MissingPackages.new(missing)
      end
    end
Verifies all {#packages}
 @return [void]
 @raise [Errors::MissingPackages] if at least one package is not build.