code: def __init__(self, id, storage_level):
      self.id = id
      self.storage_level = storage_level
  
imports: import abc
  import json
  from ..typecheck import typecheck_method, sequenceof, nullable, enumeration
  from ..expr.types import tvoid, tstr
  from ..utils.misc import escape_str
label_desc: Use image node_id 1 to create a new BlockMatrixPersistWriter object from inherited base classes: BlockMatrixWriter with example: obj = BlockMatrixPersistWriter(id, storage_level)