code: def test_rolling_corr_with_single_integer_in_index():
      # GH 44078
      df = DataFrame({"a": [(1,), (1,), (1,)], "b": [4, 5, 6]})
      gb = df.groupby(["a"])
      result = gb.rolling(2).corr(other=df)
      index = MultiIndex.from_tuples(
          [((1,), 0), ((1,), 1), ((1,), 2)], names=["a", None]
      )
      expected = DataFrame(
          {"a": [np.nan, np.nan, np.nan], "b": [np.nan, 1.0, 1.0]},
          index=index,
      )
      tm.assert_frame_equal(result, expected)
  
imports: import numpy
  import pytest
  from pandas import DataFrame, DatetimeIndex, Index, MultiIndex, Series, Timestamp, date_range, to_datetime
  import pandas._testing
  from pandas.api.indexers import BaseIndexer
  from pandas.core.groupby.groupby import get_groupby
label_desc: Use image node_id 3 for calling a global function with example usage: test_rolling_corr_with_single_integer_in_index() without return types