Can someone convert this Python 2 code into Python 3 code?

**Code:**

import re import sys import collections from operator import itemgetter

def clean_words(words): """ Removes anything but letters in word list""" cleaned = []

for i in xrange(len(words)): word = re.sub(r"[^a-zA-Z]", '', words[i]) if len(word) > 0: cleaned.append(word)

return cleaned

def book_to_wordlist(filename): """ Converts a text file to words list. """ words = [] # open book with open(filename, 'r') as _f: # read into buffer split into words and return words = clean_words( _f.read().split(" ") )

return words

def print_histo(top_20_words): """ Prints a histogram of top 20 words """ max_repeat = list( max(top_20_words, key=itemgetter(1)) )[1]

for tup in top_20_words: print "%s " % (tup[0]), # 20 *s for largest for i in xrange(tup[1] * 20 / max_repeat): sys.stdout.write("*")

print

def main(): books = [ "around_world.txt", "republic.txt", "three_musketeers.txt", "walden.txt" ]

# For each of these texts perform the following tasks for book in books: # Create a list of 20 words most frequently appearing words = book_to_wordlist(book) counter = collections.Counter(words) top20 = counter.most_common(20) print book # Plot frequencies of all words appearing in the text print_histo(top20) print

if __name__ == "__main__": main()