code: def gen_data2():
      rs = np.random.RandomState(0)
      data_size = 100
      data_dict = {
          "a": rs.randint(0, 10, size=(data_size,)),
          "b": rs.choice(list("abcd"), size=(data_size,)),
          "c": rs.choice(list("abcd"), size=(data_size,)),
          "d": rs.randint(0, 10, size=(data_size,)),
      }
      df = pd.DataFrame(data_dict)
      yield df
  
file_path: mars/mars/dataframe/groupby/tests/test_groupby_nunique_execution.py
imports: import numpy
  import pandas
  import pytest
  from ....None import dataframe
label_desc: Use image node_id 2 for calling a global function with example usage: gen_data2() without return types