How to use the piicatcher.scanner.NERScanner function in piicatcher

def setUp(self):
        self.parser = NERScanner()

)
        else:
            for root, subdirs, files in os.walk(self._path):
                for filename in files:
                    file_path = os.path.join(root, filename)
                    mime_type = magic.from_file(file_path, mime=True)

                    logging.debug(
                        "\t- full path: %s, mime_type: %s" % (file_path, mime_type)
                    )
                    self._files.append(File(file_path, mime_type))

        context = {
            "tokenizer": Tokenizer(),
            "regex": RegexScanner(),
            "ner": NERScanner(),
        }
        for f in self._files:
            f.scan(context)