code: def test_first_last(self):
      block_val = predicates.lastSetElementPredicate(self.s1)
      assert block_val == {"red"}
      block_val = predicates.firstSetElementPredicate(self.s1)
      assert block_val == {"blue"}
  
imports: import unittest
  from dedupe import predicates
label_desc: Use image node_id 4 for calling the TestSetElement obj's underlying member method code with example usage: obj.test_first_last() without return types