center.py

from functools import reduce                                                    
def center(words):
    max_length = reduce(lambda a, b: a if a > len(b) else len(b), words, 0)        
    words = [word if len(word) == max_length else '{}{}'.format(' ' * ((max_length - len(word)) // 2), word) for word in words]
    for word in words: print(word)