code: def _before_run(self, ctx):
      if self._need_run():
          return self._fetches
      return None
  
imports: import numpy
  from collections import deque
  from ..compat import tfv1
  from ..tfutils.common import get_op_tensor_name
  from ..utils import logger
  from ..utils.naming import MOVING_SUMMARY_OPS_KEY
  from .base import Callback
label_desc: Use image node_id 4 for calling the MergeAllSummaries_RunWithOp obj's underlying member method code with example usage: obj._before_run(ctx) and returns: None, self