docs: function EventDispatcher (structureSearcher, definition) {
    if (!structureSearcher || !_.isObject(structureSearcher) || !_.isFunction(structureSearcher.getSagas)) {
      var err = new Error('Please pass a valid tree!');
      debug(err);
      throw err;
    }
  
    if (!definition || !_.isObject(definition)) {
      var err = new Error('Please pass a valid command definition!');
      debug(err);
      throw err;
    }
  
    this.structureSearcher = structureSearcher;
    this.definition = definition;
  }