class_docstr: Data manager for sampling data, use reservoir sampling.
      
docstr: Pop the last item in reservoir buckets.
  
  Sometimes the tail of the retrieved data is abnormal 0. This
  method is used to handle this problem.
docstr_tok: ["Pop","the","last","item","in","reservoir","buckets",".","Sometimes","the","tail","of","the","retrieved","data","is","abnormal","0",".","This","method","is","used","to","handle","this","problem","."]
code: def cut_tail(self):
      """Pop the last item in reservoir buckets.
  
      Sometimes the tail of the retrieved data is abnormal 0. This
      method is used to handle this problem.
      """
      with self._mutex:
          self._items.pop()
          self._num_items_index -= 1
  
imports: import collections
  import random
  import threading
label_desc: Use image node_id 7 for calling the _ReservoirBucket obj's underlying member method code with example usage: obj.cut_tail() without return types