input: Write a function to combine two dictionaries of similar structure together, such that the entries in the two dictionaries are merged into a single dictionary.
  
  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':30, 'z':40})=={'x':10, 'y':30, 'z':40}
  assert merge_dict({'p':100, 'q':200}, {})=={'p':100, 'q':200}
  assert merge_dict({}, {'r':300, 's':400})=={'r':300, 's':400}
  assert merge_dict({}, {})=={}
output: def merge_dict(dict_a, dict_b):
      merged_dict = {**dict_a, **dict_b}
      return merged_dict