Use Zuban and therefore check untyped code

setup.cfg

@@ -10,20 +10,3 @@ ignore =
   E226,
   # line break before binary operator
   W503,
-
-
-[mypy]
-show_error_codes = true
-enable_error_code = ignore-without-code
-
-disallow_subclassing_any = True
-
-# Avoid creating future gotchas emerging from bad typing
-warn_redundant_casts = True
-warn_unused_ignores = True
-warn_return_any = True
-warn_unused_configs = True
-warn_unreachable = True
-
-strict_equality = True
-no_implicit_optional = False