def test_merge_dicts(self):
    self.assertEqual(merge_dicts({'a': 1}, {'b': 2}), {'a': 1, 'b': 2})
    self.assertEqual(merge_dicts({'a': 1}, {'a': 2}), {'a': 1})
    self.assertEqual(merge_dicts({'a': 1}, {'a': None}), {'a': 1})
    self.assertEqual(merge_dicts({'a': 1}, {'a': ''}), {'a': 1})
    self.assertEqual(merge_dicts({'a': 1}, {}), {'a': 1})
    self.assertEqual(merge_dicts({'a': None}, {'a': 1}), {'a': 1})
    self.assertEqual(merge_dicts({'a': ''}, {'a': 1}), {'a': ''})
    self.assertEqual(merge_dicts({'a': ''}, {'a': 'abc'}), {'a': 'abc'})
    self.assertEqual(merge_dicts({'a': None}, {'a': ''}, {'a': 'abc'}), {'a': 'abc'})
def test_merge_dicts(self):
    self.assertEqual(merge_dicts({'a': 1}, {'b': 2}), {'a': 1, 'b': 2})
    self.assertEqual(merge_dicts({'a': 1}, {'a': 2}), {'a': 1})
    self.assertEqual(merge_dicts({'a': 1}, {'a': None}), {'a': 1})
    self.assertEqual(merge_dicts({'a': 1}, {'a': }), {'a': 1})
    self.assertEqual(merge_dicts({'a': 1}, {}), {'a': 1})
    self.assertEqual(merge_dicts({'a': None}, {'a': 1}), {'a': 1})
    self.assertEqual(merge_dicts({'a': }, {'a': 1}), {'a': })
    self.assertEqual(merge_dicts({'a': }, {'a': 'abc'}), {'a': 'abc'})
    self.assertEqual(merge_dicts({'a': None}, {'a': }, {'a': 'abc'}), {'a': 'abc'})