Make @lru_cache ignore some of the function arguments

With cachetools you can write:

from cachetools import cachedfrom cachetools.keys import hashkeyfrom random import randint@cached(cache={}, key=lambda db_handle, query: hashkey(query))def find_object(db_handle, query):    print("processing {0}".format(query))    return queryqueries = list(range(5))queries.extend(range(5))for q in queries:    print("result: {0}".format(find_object(randint(0, 1000), q)))

I have at least one very ugly solution. Wrap db_handle in a object that's always equals, and unwrap it inside the function.

It requires a decorator with quite a bit of helper functions, which makes stack trace quite confusing.

class _Equals(object):    def __init__(self, o):        self.obj = o    def __eq__(self, other):        return True    def __hash__(self):        return 0def lru_cache_ignoring_first_argument(*args, **kwargs):    lru_decorator = functools.lru_cache(*args, **kwargs)    def decorator(f):        @lru_decorator        def helper(arg1, *args, **kwargs):            arg1 = arg1.obj            return f(arg1, *args, **kwargs)        @functools.wraps(f)        def function(arg1, *args, **kwargs):            arg1 = _Equals(arg1)            return helper(arg1, *args, **kwargs)        return function    return decorator