NameError: name 'filtered' is not defined

This error occurs when you try to reference a variable or function that has not been defined in the current scope.

For example, if you have code that tries to use a variable named "filtered" but you have not previously defined it in that code block or in a parent scope, you will get the "NameError: name 'filtered' is not defined" message.

To fix this error, you need to define the variable or function before you try to use it. Check your code to make sure that you have defined all necessary variables and functions in the appropriate scope.