code: def test_union_different_type_base(self, klass):
      # GH 10149
      index = Index([0, "a", 1, "b", 2, "c"])
      first = index[3:]
      second = index[:5]
  
      result = first.union(klass(second.values))
  
      assert equal_contents(result, index)
  
imports: from datetime import datetime
  import numpy
  import pytest
  import pandas
  from pandas import Index, Series
  import pandas._testing
  from pandas.core.algorithms import safe_sort
label_desc: Use image node_id 4 for calling the TestIndexSetOps obj's underlying member method code with example usage: obj.test_union_different_type_base(klass) without return types