class_docstr: A Trigger determines when a pane of a window should be evaluated to emit the results for
  that part of the window.
  
  A pane is the bucket of elements that have the same key and same Window. An element
  an be in multiple panes if it was assigned to multiple windows by the WindowAssigner.
  These panes all have their own instance of the Trigger.
  
  Triggers must not maintain state internally since they can be re-created or reused for
  different keys. All necessary state should be persisted using the state abstraction available on
  the TriggerContext.
docstr: Initialization method for the trigger. Creates states in this method.
  
  :param ctx: A context object that can be used to get states.
docstr_tok: ["Initialization","method","for","the","trigger",".","Creates","states","in","this","method",".",":","param","ctx",":","A","context","object","that","can","be","used","to","get","states","."]
code: def open(self, ctx: TriggerContext):
      """
      Initialization method for the trigger. Creates states in this method.
  
      :param ctx: A context object that can be used to get states.
      """
      pass
  
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 1 for calling the Trigger obj's underlying member method code with example usage: obj.open(ctx) without return types