text: function Arranger(partsInput) {
    var self = this;
    var parts = partsInput;
    var partsOutput = [];
  
    self.arrange = function() {
      parts.forEach(function(part) {
        console.log(part.generator.drums );
        if(part.generator instanceof DrumMachine) {
          part.generator.drums().forEach(function(drum){
            partsOutput.push(new Part(drum, part.rhythm[drum.name()]))
          });
        }
        else {
          partsOutput.push(part);
        }
      });
      return partsOutput;
    }
  }