input: Write a function to merge two dictionaries of similar structure together, such that the entries in the two dictionaries are merged into a single dictionary.
  
  ### Input:
  dict_a = {'a':1, 'b':2, 'c':3}
  dict_b = {'d':4, 'e':5, 'f':6}
  
  ### Output:
  def merge_dict(dict_a, dict_b):
      merged_dict = {**dict_a, **dict_b}
      return merged_dict
  assert merge_dict({'a':1, 'b':2, 'c':3}, {'d':4, 'e':5, 'f':6})=={'a': 1, 'b': 2, 'c': 3, 'd': 4, 'e': 5, 'f': 6}
  assert merge_dict({'x':10, 'y':20}, {'y':25, 'z':30})=={'x': 10, 'y': 25, 'z': 30}
  assert merge_dict({}, {'a':1, 'b':2})=={'a': 1, 'b': 2}
  assert merge_dict({'a':1}, {})=={'a': 1}
  assert merge_dict({}, {})=={}
output: def merge_dict(dict_a, dict_b):
      merged_dict = {**dict_a, **dict_b}
      return merged_dict