code: def test_cov_nullable_integer(self, other_column):
      # https://github.com/pandas-dev/pandas/issues/33803
      data = DataFrame({"a": pd.array([1, 2, None]), "b": other_column})
      result = data.cov()
      arr = np.array([[0.5, 0.5], [0.5, 1.0]])
      expected = DataFrame(arr, columns=["a", "b"], index=["a", "b"])
      tm.assert_frame_equal(result, expected)
  
imports: import numpy
  import pytest
  import pandas.util._test_decorators
  import pandas
  from pandas import DataFrame, Index, Series, date_range, isna
  import pandas._testing
label_desc: Use image node_id 3 for calling the TestDataFrameCov obj's underlying member method code with example usage: obj.test_cov_nullable_integer(other_column) without return types