getObjectSchema(key) {
    const newSchemaDef = {};
    const genericKey = MongoObject.makeKeyGeneric(key);
    const searchString = `${genericKey}.`;

    const mergedSchema = this.mergedSchema();
    Object.keys(mergedSchema).forEach((k) => {
      if (k.indexOf(searchString) === 0) {
        newSchemaDef[k.slice(searchString.length)] = mergedSchema[k];
      }
    });

    return this._copyWithSchema(newSchemaDef);
  }
Given a key that is an Object, returns a new SimpleSchema instance scoped to that object.

@param {String} key Generic or specific schema key