Merge pull request #132 from Toloka/no_strict_optional_mypy

Run mypy with --no-strict-optional

tox.ini

@@ -34,7 +34,7 @@ commands =
     autoquality: pytest tests/import_tests/test_autoquality.py -vv
     zookeeper: pytest tests/import_tests/test_zookeper.py -vv
     jupyter-metrics: pandas: pytest tests/import_tests/test_jupyter_metrics.py -vv
-    attrs21-all: mypy src
+    attrs21-all: mypy --no-strict-optional src
     attrs21-all: flake8 --select=E,W,F --ignore=E122,E123,E127,E131,E203,E225,E226,E24,E275,E305,E306,E402,E722,E731,E741,F722,W503,W504,C9,N8 --max-line-length=200 src
 
 extras =
@@ -58,7 +58,7 @@ passenv =
 commands =
     coverage run --source {envsitepackagesdir}/toloka/client -m pytest tests
     codecov
-    mypy src/client
+    mypy --no-strict-optional src/client
 
 # Test that stubs can be generated
 [testenv:py310-stubgeneration-all]