code: def _trigger(self):
      if self.summary_op:
          summary = self.summary_op.eval()
          self.trainer.monitors.put_summary(summary)
  
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_RunAlone obj's underlying member method code with example usage: obj._trigger() without return types