docs: function deleteGroup(connections, options, groupParams, cb) {
    var validate = validation(groupParams);
    function validateParams(cb) {
      validate.has("_id", cb);
    }
    validateParams(function(err) {
      if (err) {
        return cb(err);
      }
      var conn = connections.mongooseConnection;
      var groupsModel = models.get(conn, models.MODELNAMES.GROUPS);
      groupsModel.findById(groupParams._id).remove(cb);
    });
  }