code: def _type(self):
      return tvoid
  
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 3 for calling the BlockMatrixNativeWriter obj's underlying member method code with example usage: obj._type() and returns: tvoid