def merge_two_dicts(a, b):
 
 
   c = a.copy()   # make a copy of a
 
   c.update(b)    # modify keys and values of a with the ones from b
 
   return c
 
 
 
 
 
a = { 'x': 1, 'y': 2}
 
b = { 'y': 3, 'z': 4}
 
 
print(merge_two_dicts(a, b)) # {'y': 3, 'x': 1, 'z': 4}