code: def test_size_series_masked_type_returns_Int64(dtype):
      # GH 54132
      ser = Series([1, 1, 1], index=["a", "a", "b"], dtype=dtype)
      result = ser.groupby(level=0).size()
      expected = Series([2, 1], dtype="Int64", index=["a", "b"])
      tm.assert_series_equal(result, expected)
  
file_path: pandas/pandas/tests/groupby/methods/test_size.py
imports: import numpy
  import pytest
  import pandas.util._test_decorators
  from pandas.core.dtypes.common import is_integer_dtype
  from pandas import DataFrame, Index, PeriodIndex, Series
  import pandas._testing
label_desc: Use image node_id 8 for calling a global function with example usage: test_size_series_masked_type_returns_Int64(dtype) without return types