code: def _trigger_step(self):
      if self._period:
          if (self.local_step + 1) % self._period == 0:
              self._trigger()
  
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 3 for calling the MergeAllSummaries_RunAlone obj's underlying member method code with example usage: obj._trigger_step() without return types