code: def setup(self, threads, method):
      N = 10**6
      ngroups = 10**3
      df = DataFrame(
          {
              "key": np.random.randint(0, ngroups, size=N),
              "data": np.random.randn(N),
          }
      )
  
      @test_parallel(num_threads=threads)
      def parallel():
          getattr(df.groupby("key")["data"], method)()
  
      self.parallel = parallel
  
      def loop():
          getattr(df.groupby("key")["data"], method)()
  
      self.loop = loop
  
imports: from functools import wraps
  import threading
  import numpy
  from pandas import DataFrame, Index, Series, date_range, factorize, read_csv
  from pandas.core.algorithms import take_nd
  from .pandas_vb_common import BaseIO
  from .pandas_vb_common import setup
label_desc: Use image node_id 1 for calling the ParallelGroupbyMethods obj's underlying member method code with example usage: obj.setup(threads, method) without return types