class_docstr: Window node.
code: def _get_buffer(self):
      while True:
          data = self.input_que.get_dict()
          if data is None:
              # end of the data_queue
              if self.buffer is not None and self.buffer.data:
                  ret = self.buffer.data
                  self.buffer = self.buffer.next()
                  return self._to_cols(ret)
              self._set_finished()
              return None
  
          if not self.side_by_to_next(data):
              return None
  
          process_data = dict(
              (key, data.get(key))
              for key in self._node_repr.inputs
              if data.get(key) is not Empty()
          )
  
          if not process_data:
              continue
  
          index = self._window_index(data)
          if index < 0:
              continue
  
          if self.buffer(process_data, index) and self.buffer.data:
              ret = self.buffer.data
              self.buffer = self.buffer.next()
              return self._to_cols(ret)
  
file_path: towhee/towhee/runtime/nodes/_window_base.py
imports: from typing import List, Dict
  from towhee.runtime.data_queue import Empty
  from towhee.runtime.time_profiler import Event
  from .node import Node
  from ._single_input import SingleInputMixin
label_desc: Use image node_id 6 for calling the WindowBase obj's underlying member method code with example usage: obj._get_buffer() and returns: None, None, self, self