style: format code with Black

[deepsource-autofix]

This commit fixes the style issues introduced in 6c5d27c according to the output
from Black.

Details: None

[pep8speaks]

Hello @deepsource-autofix[bot]! Thanks for opening this PR. We checked the lines you've touched for PEP 8 issues, and found:

• In the file tests/test_main.py:

Line 32:80: E501 line too long (88 > 79 characters)
Line 40:80: E501 line too long (88 > 79 characters)