Prepare for fully typechecked codebase

mypy.ini

@@ -0,0 +1,31 @@
+[mypy]
+python_version = 3.7
+#warn_return_any = True
+warn_unused_configs = True
+disallow_untyped_calls = True
+disallow_untyped_defs = True
+disallow_incomplete_defs = True
+#check_untyped_defs = True
+disallow_untyped_decorators = False
+#disallow_any_unimported = True
+#disallow_any_expr = True
+#disallow_any_decorated = True
+disallow_any_explicit = False
+#disallow_any_generics = True
+disallow_subclassing_any = False
+no_implicit_optional = True
+warn_redundant_casts = True
+warn_unused_ignores = True
+warn_unreachable = True
+
+[mypy-hsluv.*]
+ignore_missing_imports = True
+
+[mypy-flask_wtf.*]
+ignore_missing_imports = True
+
+[mypy-flask_babel.*]
+ignore_missing_imports = True
+
+[mypy-wtforms.*]
+ignore_missing_imports = True