TypeError: config must be a filename or Config object, but got <class 'NoneType'>

This error occurs when you are trying to use a variable or object that is of type NoneType where a filename or Config object is expected.

To resolve this error, you need to ensure that the variable or object you are using is of the correct type. If you are trying to use a filename, make sure the variable contains the correct filename and that the file exists in the specified location. If you are trying to use a Config object, make sure the variable is initialized as a Config object and contains the necessary configuration data.

If the variable or object is not initialized, you need to initialize it before using it. You can also check if the variable or object is None using the 'is' operator and handle the case where it is None appropriately.