docs: function _getIdentityFields(Model, record, identityFields = []) {
  
      /*
       * Definition holds the schema
       * inforamtion of your model.
       */
      let schema = Model.definition;
  
      let definition;
      /*
       * Collect all unique keys in schema.
       * We can check record and see if we have
       * any present that we did not specify in
       * our `identityFields`.
       * If we do, we are good.
       */
      Object.keys(schema).map(key => {
          definition = schema[key];
          if (definition.unique) {
              if (!identityFields.includes(key)) {
                  identityFields.push(key);
              }
          }
      });
  
      return identityFields;
  }