Cat age converter

cat_age_converter.py

"""Convert cat years to human years."""

# Build conversion dictionary: keys are cat years, values are human years.
conversion = {1: 15}

for age in (2, 3):
    conversion[age] = conversion[age - 1] + 6

for age in range(4, 21):
    conversion[age] = conversion[age - 1] + 4

cat_age = int(input("Enter your cat's age in years: "))
human_age = conversion.get(cat_age)

if human_age:
    print(f"In human years, your cat would be {human_age} years old.")
else:
    print("Please enter your cat's actual age (1 - 20).")