Create incrementors

In order to use in various map-expressions, we need a couple of functions that - for simplicity - need to increment a number:

def f3(x):
    return x + 3

def f7(x):
    return x + 7

def f23(x):
    return x + 23

print(f3(2))
print(f7(3))
print(f3(4))
print(f7(10))
print(f23(19))

5
10
7
17
42