how to make list of keys which has same values

1# Python code to demonstrate 
2# finding duplicate values from dictionary 
3
4# initialising dictionary 
5ini_dict = {'a':1, 'b':2, 'c':3, 'd':2} 
6
7# printing initial_dictionary 
8print("initial_dictionary", str(ini_dict)) 
9
10# finding duplicate values 
11# from dictionary using flip 
12flipped = {} 
13
14for key, value in ini_dict.items(): 
15	if value not in flipped: 
16		flipped[value] = [key] 
17	else: 
18		flipped[value].append(key) 
19
20# printing result 
21print("final_dictionary", str(flipped)) 
22