class_docstr: A Trigger that fires once the count of elements in a pane reaches the given count.
code: def on_element(self, element, timestamp, window: W) -> bool:
      count_state = self._ctx.get_partitioned_state(
          self._count_state_desc
      )
      count = count_state.value()
      if count is None:
          count = 0
      count += 1
      count_state.update(count)
      if count >= self._count_elements:
          count_state.clear()
          return True
      else:
          return False
  
imports: from abc import abstractmethod, ABC
  from typing import Generic
  from pyflink.common.typeinfo import Types
  from pyflink.datastream.state import ValueStateDescriptor
  from pyflink.datastream.window import TimeWindow, CountWindow
  from pyflink.fn_execution.table.window_context import TriggerContext, W
label_desc: Use image node_id 3 for calling the CountTrigger obj's underlying member method code with example usage: obj.on_element(element, timestamp, window) and returns: True, False