code: function entitiesToDatastore(entities, options) {
      const multiple = is.array(entities);
      entities = arrify(entities);
  
      if (entities[0].className !== 'Entity') {
          // Not an entity instance, nothing to do here...
          return entities;
      }
  
      const result = entities.map(e => toDatastore(e, options));
  
      return multiple ? result : result[0];
  }
docs: Convert one or several entities instance (gstore) to Datastore format
  
  @param {any} entities Entity(ies) to format
  @returns {array} the formated entity(ies)