# File lib/serverspec/type/package.rb, line 3
    def installed?(provider=nil, version=nil)
      if provider.nil?
        @inspection = Specinfra.command.get(:check_package_is_installed, @name, version)
        @runner.check_package_is_installed(@name, version)
      else
        check_method = "check_package_is_installed_by_#{provider}".to_sym
        @runner.send(check_method, @name, version)
      end
    end