code: def add_disk(self, path, force_disk_indexes=True, **args):
          
          if self.disks and self.disks[0].index is None:
              raise DiskIndexError("First disk has no index.")
  
          if force_disk_indexes or self.disks:
              index = len(self.disks) + 1
          else:
              index = None
          disk = Disk(self, path, index=str(index) if index else None, **args)
          self.disks.append(disk)
          return disk
docs: Adds a disk specified by the path to the ImageParser.
  
          :param path: The path to the disk volume
          :param force_disk_indexes: If true, always uses disk indexes. If False, only uses disk indexes if this is the
                                     second volume you add. If you plan on using this method, always leave this True.
                                     If you add a second disk when the previous disk has no index, an error is raised.
          :param args: Arguments to pass to the constructor of the Disk.