docs: function Accumulator(name, deps, fragment, resultsFn, options) {
    if (!(this instanceof Accumulator)) {
      return new Accumulator(name, deps, fragment, resultsFn, options);
    }
  
    Task.apply(this, Array.prototype.slice.call(arguments));
  
    this.fragment = fragment;
  
    if (!_.isFunction(resultsFn)) {
      throw new Error('You must provide a function to indicate when the accumulator is complete');
    }
  
    this.resultsFn = resultsFn;
    this.options = options || {};
  }