docs: def info_installed(*names, **kwargs):
      '''
      Return the information of the named package(s), installed on the system.
  
      .. versionadded:: 2017.7.0
  
      :param names:
          Names of the packages to get information about. If none are specified,
          will return information for all installed packages.
  
      :param attr:
          Comma-separated package attributes. If no 'attr' is specified, all available attributes returned.
  
          Valid attributes are:
              arch, conffiles, conflicts, depends, description, filename, group,
              install_date_time_t, md5sum, packager, provides, recommends,
              replaces, size, source, suggests, url, version
  
      CLI example:
  
      .. code-block:: bash
  
          salt '*' pkg.info_installed
          salt '*' pkg.info_installed attr=version,packager
          salt '*' pkg.info_installed <package1>
          salt '*' pkg.info_installed <package1> <package2> <package3> ...
          salt '*' pkg.info_installed <package1> attr=version,packager
          salt '*' pkg.info_installed <package1> <package2> <package3> ... attr=version,packager
      '''
      attr = kwargs.pop('attr', None)
      if attr is None:
          filter_attrs = None
      elif isinstance(attr, six.string_types):
          filter_attrs = set(attr.split(','))
      else:
          filter_attrs = set(attr)
  
      ret = {}
      if names:
          # Specific list of names of installed packages
          for name in names:
              cmd = ['opkg', 'status', name]
              call = __salt__['cmd.run_all'](cmd,
                                             output_loglevel='trace',
                                             python_shell=False)
              if call['retcode'] != 0:
                  comment = ''
                  if call['stderr']:
                      comment += call['stderr']
                  else:
                      comment += call['stdout']
  
                  raise CommandExecutionError(comment)
              ret.update(_process_info_installed_output(call['stdout'], filter_attrs))
      else:
          # All installed packages
          cmd = ['opkg', 'status']
          call = __salt__['cmd.run_all'](cmd,
                                         output_loglevel='trace',
                                         python_shell=False)
          if call['retcode'] != 0:
              comment = ''
              if call['stderr']:
                  comment += call['stderr']
              else:
                  comment += call['stdout']
  
              raise CommandExecutionError(comment)
          ret.update(_process_info_installed_output(call['stdout'], filter_attrs))
  
      return ret