Total Characters in String After Transformations I

Description

You are given a string s and an integer t representing how many transformations to apply. In each transformation, every character in s is replaced according to these rules:

- The character 'z' becomes the string "ab".

- Any other character advances to the next letter in the alphabet (e.g., 'a' becomes 'b', 'b' becomes 'c', and so on).

Return the length of the resulting string after exactly t transformations.

Since the answer may be very large, return it modulo 109 + 7.

Code

class Solution:
    def lengthAfterTransformations(self, s: str, t: int) -> int: