Union in source code doesn't work with old python3 version

[bayram-dev]

Python 3.9.21
soft-assert==1.0.5

I get an error trying to use library

test.py:5: in <module>
    from soft_assert import check, verify
.local/lib/python3.9/site-packages/soft_assert/__init__.py:1: in <module>
    from .soft_assert import (
.local/lib/python3.9/site-packages/soft_assert/soft_assert.py:16: in <module>
    def get_last_failure() -> str | None:

The reasons why -- this feature announced in version Python >= 3.10

• https://docs.python.org/3.10/whatsnew/3.10.html#pep-604-new-type-union-operator
• https://peps.python.org/pep-0604/ (Python-Version: 3.10)