I'd like to align two lists in a similar way to what difflib.Differ would do except I want to be able to define a match function for comparing items, not just use string equality, and preferably a match function that can return a number between 0.0 and 1.0, not just a boolean.

So, for example, say I had the two lists:

L1 = [('A', 1), ('B', 3), ('C', 7)]
L2 = ['A', 'b', 'C']

and I want to be able to write a match function like this:

def match(item1, item2):
    if item1[0] == item2:
        return 1.0
    elif item1[0].lower() == item2.lower():
        return 0.5
    else:
        return 0

and then do:

d = Differ(match_func=match)
d.compare(L1, L2)

and have it diff using the match function. Like difflib, I'd rather the algorithm gave more intuitive Ratcliff-Obershelp type results rather than a purely minimal Levenshtein distance.