def process_only_even(n):
if n % 2 == 1:
return 'This was an odd number!'
print('Very interesting number ...', n)
n += 18
print('Adding 18 will result in:', n)
return n
print(process_only_even(5))
# This was an odd number!
print(process_only_even(6))
# Very interesting number ... 6
# Adding 18 will result in: 24
# 24