def METHOD_NAME(self):
    self.test_data = [
        ["item number one", "item number two", "item number three", "item number four"],
        ["item number five"],
        [
            "item number six",
            "item number seven",
            "item number eight",
            "item number nine",
            "item number ten",
            "item number eleven",
        ],
        ["item number twelve", "item number thirteen", "item number fourteen",],
    ]
    self.flattened_test_data = []
    for chunk in self.test_data:
        for item in chunk:
            self.flattened_test_data.append(item)
    self.data_dir = tempfile.mkdtemp()
    self.chunk_file_paths = []
    for chunk_id, chunk in enumerate(self.test_data):
        file_name = os.path.join(self.data_dir, "chunk_" + str(chunk_id).zfill(10) + ".gz")
        self.chunk_file_paths.append(file_name)
        file_content = "\n".join(chunk)
        with gzip.open(file_name, "wt", encoding="utf-8") as f:
            f.write(file_content)