docs: def group_members(self, group):
          """Return a hash or users with their information. Requires JIRA 6.0 or will raise NotImplemented.
  
          :param group: Name of the group.
          :type group: str
          """
          if self._version < (6, 0, 0):
              raise NotImplementedError(
                  "Group members is not implemented in JIRA before version 6.0, upgrade the instance, if possible.")
  
          params = {'groupname': group, 'expand': "users"}
          r = self._get_json('group', params=params)
          size = r['users']['size']
          end_index = r['users']['end-index']
  
          while end_index < size - 1:
              params = {'groupname': group, 'expand': "users[%s:%s]" % (
                  end_index + 1, end_index + 50)}
              r2 = self._get_json('group', params=params)
              for user in r2['users']['items']:
                  r['users']['items'].append(user)
              end_index = r2['users']['end-index']
              size = r['users']['size']
  
          result = {}
          for user in r['users']['items']:
              result[user['key']] = {'name': user['name'],
                                     'fullname': user['displayName'],
                                     'email': user.get('emailAddress', 'hidden'),
                                     'active': user['active']}
          return OrderedDict(sorted(result.items(), key=lambda t: t[0]))