Python, given a word, generate a list with one letter changing for each letter in alphabet
Just use regular expressions!

import re
# creating regular expression with "any" letter at 3 position
r = re.compile("co[a-z]e")
# and taking all the matches:
matches = r.findall("some of my code, nope to come, cofe and cole, or cope and dome, rope and hope!")
count = len(matches)
print(count)