Speed Me Up Scotty

Before:

def my_func2_inner(x, y, a, b):
    if a == 0 or b == 0:
        return 0, ""
    if x[a - 1] == y[b - 1]:
        m, n = my_func2_inner(x, y, a - 1, b - 1)
        return m + 1, n + x[a - 1]
    return max(my_func2_inner(x, y, a, b - 1), my_func2_inner(x, y, a - 1, b))

After:

from functools import lru_cache

@lru_cache
def my_func2_inner(x, y, a, b):
    if a == 0 or b == 0:
        return 0, ""
    if x[a - 1] == y[b - 1]:
        m, n = my_func2_inner(x, y, a - 1, b - 1)
        return m + 1, n + x[a - 1]
    return max(my_func2_inner(x, y, a, b - 1), my_func2_inner(x, y, a - 1, b))