input: Write a python function to merge two dictionaries.
  assert merge_dictionaries({'a': 1, 'b': 2}, {'b': 3, 'c': 4}) == {'a': 1, 'b': 3, 'c': 4}
  assert merge_dictionaries({'x': 10, 'y': 20}, {'y': 30, 'z': 40}) == {'x': 10, 'y': 30, 'z': 40}
  assert merge_dictionaries({'name': 'Alice'}, {'age': 25, 'city': 'NY'}) == {'name': 'Alice', 'age': 25, 'city': 'NY'}
output: def merge_dictionaries(dict1, dict2):
      merged_dict = dict1.copy()
      merged_dict.update(dict2)
      return merged_dict