How to use the fakeredis._server.Float.decode function in fakeredis

if numkeys < 1:
            raise redis.ResponseError(ZUNIONSTORE_KEYS_MSG)
        if numkeys > len(args):
            raise redis.ResponseError(SYNTAX_ERROR_MSG)
        aggregate = b'sum'
        sets = []
        for i in range(numkeys):
            item = CommandItem(args[i], self._db, item=self._db.get(args[i]), default=ZSet())
            sets.append(self._get_zset(item.value))
        weights = [1.0] * numkeys

        i = numkeys
        while i < len(args):
            arg = args[i]
            if casematch(arg, b'weights') and i + numkeys < len(args):
                weights = [Float.decode(x) for x in args[i + 1:i + numkeys + 1]]
                i += numkeys + 1
            elif casematch(arg, b'aggregate') and i + 1 < len(args):
                aggregate = casenorm(args[i + 1])
                if aggregate not in (b'sum', b'min', b'max'):
                    raise redis.ResponseError(SYNTAX_ERROR_MSG)
                i += 2
            else:
                raise redis.ResponseError(SYNTAX_ERROR_MSG)

        out_members = set(sets[0])
        for s in sets[1:]:
            if func == 'ZUNIONSTORE':
                out_members |= set(s)
            else:
                out_members.intersection_update(s)

def incrbyfloat(self, key, amount):
        # TODO: introduce convert_order so that we can specify amount is Float
        c = Float.decode(key.get(b'0')) + Float.decode(amount)
        if not isfinite(c):
            raise redis.ResponseError(NONFINITE_MSG)
        encoded = Float.encode(c, True)
        key.update(encoded)
        return encoded

xx = True
                i += 1
            else:
                # First argument not matching flags indicates the start of
                # score pairs.
                break

        if nx and xx:
            raise redis.ResponseError(ZADD_NX_XX_ERROR_MSG)

        elements = args[i:]
        if not elements or len(elements) % 2 != 0:
            raise redis.ResponseError(SYNTAX_ERROR_MSG)
        # Parse all scores first, before updating
        items = [
            (Float.decode(elements[j]), elements[j + 1])
            for j in range(0, len(elements), 2)
        ]
        old_len = len(zset)
        changed_items = 0

        for item_score, item_name in items:
            if (
                (not nx or item_name not in zset)
                and (not xx or item_name in zset)
            ):
                if zset.add(item_name, item_score):
                    changed_items += 1

        if changed_items:
            key.updated()

def decode(cls, value):
        try:
            exclusive = False
            if value[:1] == b'(':
                exclusive = True
                value = value[1:]
            value = Float.decode(
                value, allow_leading_whitespace=True, allow_erange=True,
                allow_empty=True, crop_null=True)
            return cls(value, exclusive)
        except redis.ResponseError:
            raise redis.ResponseError(INVALID_MIN_MAX_FLOAT_MSG)