code: def save(filepath, obj, compressed=True):
      
      if not isinstance(obj, Multitrack):
          raise TypeError("Support only `pypianoroll.Multitrack` class objects")
      obj.save(filepath, compressed)
docs: Save the object to a .npz file.
  
      Parameters
      ----------
      filepath : str
          The path to save the file.
      obj: `pypianoroll.Multitrack` objects
          The object to be saved.