Remove an unnecessary import

# Copyright 2024 Dom Sekotill <dom.sekotill@kodo.org.uk>

# Copyright 2024, 2026 Dom Sekotill <dom.sekotill@kodo.org.uk>

#

# Licensed under the Apache License, Version 2.0 (the "License");

# you may not use this file except in compliance with the License.

from typing import Generic

from typing import Self

from typing import TypeVar

from typing import overload

U = TypeVar("U", bound="QuantityUnit")