code: def test_ngroup_distinct(self):
      df = DataFrame({"A": list("abcde")})
      g = df.groupby("A")
      sg = g.A
  
      expected = Series(range(5), dtype="int64")
  
      tm.assert_series_equal(expected, g.ngroup())
      tm.assert_series_equal(expected, sg.ngroup())
  
imports: from itertools import product
  from string import ascii_lowercase
  import numpy
  import pytest
  from pandas import DataFrame, Index, MultiIndex, Period, Series, Timedelta, Timestamp, date_range
  import pandas._testing
label_desc: Use image node_id 7 for calling the TestCounting obj's underlying member method code with example usage: obj.test_ngroup_distinct() without return types