code: def test_doesnt_contain_all_the_things(self):
      idx = Index([np.nan])
      assert not idx.isin([0]).item()
      assert not idx.isin([1]).item()
      assert idx.isin([np.nan]).item()
  
imports: import numpy
  import pytest
  import pandas
  from pandas import Index, Series
  import pandas._testing
label_desc: Use image node_id 15 for calling the TestFloatNumericIndex obj's underlying member method code with example usage: obj.test_doesnt_contain_all_the_things() without return types