class FakeSdp:
    def __init__(self, /, get_value=None, extend_exists=None, get_alt_value=None, populate=None):
        self.get_value = get_value
        self.extend_exists = extend_exists
        self.populate_function = populate
        self.get_alt_value = get_alt_value

    def get(self, cache_name, key):
        return self.get_value(cache_name, key)

    def exists(self, cache_name, key):
        return self.extend_exists(cache_name, key)

    def alt_get(self, cache_name, key):
        return self.get_alt_value(cache_name, key)

    def populate(self):
        return self.populate_function() if callable(self.populate_function) else self.populate_function