Invalid configuration object. Webpack has been initialised using a configuration object that does not match the API schema. code example

Example 1: ValidationError: Invalid options object. Sass Loader has been initialized using an options object that does not match the API schema.

npm uninstall --save-dev sass-loader
npm install --save-dev sass-loader@7.1.0

Example 2: Error: The file/path provided (flaskr) does not appear to exist. Please verify the path is correct. If app is not on PYTHONPATH, ensure the extension is .py

pip install -U flask