func: Dictionary remembers added order of items.
Ref : https://docs.python.org/3/library/collections.html
Usecase sample : convert number to roman numerals.
import string
from collections import OrderedDict
def to_roman(num):
maps = OrderedDict([('M', 1000), ('CM', 900), ('D', 500),
('CD', 400), ('C', 100), ('XC', 90), ('L', 50), ('XL', 40),
('X', 10), ('IX', 9), ('V', 5), ('IV', 4), ('I', 1)])
res = ''
for k, v in maps.items():
while num >= v:
print(f' {num}, {v}')
res += k
num -= v
return res
print(1988)
print(to_roman(1988))
### output #####
1988
1988, 1000
988, 900
88, 50
38, 10
28, 10
18, 10
8, 5
3, 1
2, 1
1, 1
MCMLXXXVIII
