utilities/handler-helper.js
function _update(model, _id, payload, Log) {
  let request = { params: { _id: _id }, payload: payload }
  return _updateHandler(model, _id, request, Log)
}
function _update(model, _id, payload, Log) {
  let request = { params: { _id: _id }, payload: payload }
  return _updateHandler(model, _id, request, Log)
}
function _update ( model , _id , payload , Log ) { let request = { params : { _id : _id } , payload : payload } return _updateHandler ( model , _id , request , Log ) }
Update function exposed as a mongoose wrapper.
@param model: A mongoose model.
@param _id: The document id.
@param payload: Data used to update the model document.
@param Log: A logging object.
@returns {object} A promise for the resulting model document.
@private
Update function exposed as a mongoose wrapper .