;
        } else {
          flat.push(b);
        }
      }, this);
      return flat;
    },

    _prepAllBehaviors: function() {
      // filter so other iterators don't need null check
      this.behaviors = this.behaviors.filter(function(b) {
        if (b) {
          this._mixinBehavior(b);
          this._prepBehavior(b);
          return true;
        }
        this._warn(this._logf('_prepAllBehaviors', 'behavior is null, check for missing or 404 import'));
      }, this);
      this._prepBehavior(