code: def hll_count(expr, error_rate=0.01, splitter=None):
      
  
      # to make the class pickled right by the cloudpickle
      with open(os.path.join(path, 'lib', 'hll.py')) as hll_file:
          local = {}
          six.exec_(hll_file.read(), local)
          HyperLogLog = local['HyperLogLog']
  
          return expr.agg(HyperLogLog, rtype=types.int64, args=(error_rate, splitter))
docs: Calculate HyperLogLog count
  
      :param expr:
      :param error_rate: error rate
      :type error_rate: float
      :param splitter: the splitter to split the column value
      :return: sequence or scalar
  
      :Example:
  
      >>> df = DataFrame(pd.DataFrame({'a': np.random.randint(100000, size=100000)}))
      >>> df.a.hll_count()
      63270
      >>> df.a.nunique()
      63250