code: function EntityInstantiator(options) {
    if (!options.store) throw new Error("Missing store");
    if (!options.Entity) throw new Error("Missing entity constructor");
    if (!options.logger) throw new Error("Missing logger");
    this.store  = options.store;
    this.Entity = options.Entity;
    this.logger = options.logger;
  }
docs: todo: use one instance all the time?