input: Write a python function to merge two dictionaries.
  assert mergeDictionaries({'a': 1, 'b': 2}, {'c': 3, 'd': 4}) == {'a': 1, 'b': 2, 'c': 3, 'd': 4}
  assert mergeDictionaries({'x': 10, 'y': 20}, {'y': 30, 'z': 40}) == {'x': 10, 'y': 30, 'z': 40}
  assert mergeDictionaries({}, {'a': 1}) == {'a': 1}
output: def mergeDictionaries(dict1, dict2):
      merged_dict = dict1.copy()
      merged_dict.update(dict2)
      return merged_dict