class_docstr: Writes summary data for visualization in TensorBoard.
  
  This class is not thread-safe.
  
  TODO(#4581): This API should be considered EXPERIMENTAL and subject to
  backwards-incompatible changes without notice.
class_docstr_tok: ["Writes","summary","data","for","visualization","in","TensorBoard",".","This","class","is","not","thread-safe",".","TODO","(","#","4581",")",":","This","API","should","be","considered","EXPERIMENTAL","and","subject","to","backwards-incompatible","changes","without","notice","."]
code: def _check_not_closed(self):
      if self._closed:
          raise RuntimeError("Writer is already closed")
  
file_path: tensorboard/tensorboard/summary/_writer.py
imports: import time
  import numpy
  from tensorboard.plugins.scalar import metadata
  from tensorboard.summary import _output
label_desc: Use image node_id 2 for calling the Writer obj's underlying member method code with example usage: obj._check_not_closed() without return types