code: def test_first_last_nth_dtypes2():
      # GH 2763, first/last shifting dtypes
      idx = list(range(10))
      idx.append(9)
      ser = Series(data=range(11), index=idx, name="IntCol")
      assert ser.dtype == "int64"
      f = ser.groupby(level=0).first()
      assert f.dtype == "int64"
  
imports: import numpy
  import pytest
  import pandas
  from pandas import DataFrame, Index, MultiIndex, Series, Timestamp, isna
  import pandas._testing
label_desc: Use image node_id 7 for calling a global function with example usage: test_first_last_nth_dtypes2() without return types