input: Write a python function to update a dictionary with new key-value pairs.
  assert update_dict({"name": "John", "age": 20, "species": "Human"}, {"name": "Alex", "species": "AI"}) == {'name': 'Alex', 'age': 20, 'species': 'AI'}
  assert update_dict({"a": 1, "b": 2}, {"b": 3, "c": 4}) == {'a': 1, 'b': 3, 'c': 4}
  assert update_dict({"x": 10}, {"y": 20, "z": 30}) == {'x': 10, 'y': 20, 'z': 30}
output: def update_dict(original_dict, new_dict):
      original_dict.update(new_dict)
      return original_dict