Find and Replace Pattern

You have a list of words and a pattern, and you want to know which words in words matches the pattern.

A word matches the pattern if there exists a permutation of letters p so that after replacing every letter x in the pattern with p(x), we get the desired word.

(Recall that a permutation of letters is a bijection from letters to letters: every letter maps to another letter, and no two letters map to the same letter.)

Return a list of the words in words that match the given pattern. 

You may return the answer in any order.

Example 1:

**Input: **words = ["abc","deq","mee","aqq","dkd","ccc"], pattern = "abb"
**Output: **["mee","aqq"]
**Explanation: **"mee" matches the pattern because there is a permutation {a -> m, b -> e, ...}. 
"ccc" does not match the pattern because {a -> c, b -> c, ...} is not a permutation,
since a and b map to the same letter.

Note:

• 1 <= words.length <= 50- 1 <= pattern.length = words[i].length <= 20

def F(w):
    m = {}
    return [m.setdefault(c, len(m)) for c in w]
return [w for w in words if F(w) == F(pattern)]