def METHOD_NAME(base_filename: str, feature_filename: str, parser_only: bool, secondary_filename: str = None):
    """
    Tests whether the additional code inside of `feature_filename` was implemented in `base_filename`. This should be
    used when testing to see if `complete_*_.py` examples have all of the implementations from each of the
    `examples/by_feature/*` scripts.
    It utilizes `nlp_example.py` to extract out all of the repeated training code, so that only the new additional code
    is examined and checked. If something *other* than `nlp_example.py` should be used, such as `cv_example.py` for the
    `complete_cv_example.py` script, it should be passed in for the `secondary_filename` parameter.
    Args:
        base_filename (`str` or `os.PathLike`):
            The filepath of a single "complete" example script to test, such as `examples/complete_cv_example.py`
        feature_filename (`str` or `os.PathLike`):
            The filepath of a single feature example script. The contents of this script are checked to see if they
            exist in `base_filename`
        parser_only (`bool`):
            Whether to compare only the `main()` sections in both files, or to compare the contents of
            `training_loop()`
        secondary_filename (`str`, *optional*):
            A potential secondary filepath that should be included in the check. This function extracts the base
            functionalities off of "examples/nlp_example.py", so if `base_filename` is a script other than
            `complete_nlp_example.py`, the template script should be included here. Such as `examples/cv_example.py`
    """
    with open(base_filename, "r") as f:
        base_file_contents = f.readlines()
    with open(os.path.abspath(os.path.join("examples", "nlp_example.py")), "r") as f:
        full_file_contents = f.readlines()
    with open(feature_filename, "r") as f:
        feature_file_contents = f.readlines()
    if secondary_filename is not None:
        with open(secondary_filename, "r") as f:
            secondary_file_contents = f.readlines()
    # This is our base, we remove all the code from here in our `full_filename` and `feature_filename` to find the new content
    if parser_only:
        base_file_func = clean_lines(get_function_contents_by_name(base_file_contents, "main"))
        full_file_func = clean_lines(get_function_contents_by_name(full_file_contents, "main"))
        feature_file_func = clean_lines(get_function_contents_by_name(feature_file_contents, "main"))
        if secondary_filename is not None:
            secondary_file_func = clean_lines(get_function_contents_by_name(secondary_file_contents, "main"))
    else:
        base_file_func = clean_lines(get_function_contents_by_name(base_file_contents, "training_function"))
        full_file_func = clean_lines(get_function_contents_by_name(full_file_contents, "training_function"))
        feature_file_func = clean_lines(get_function_contents_by_name(feature_file_contents, "training_function"))
        if secondary_filename is not None:
            secondary_file_func = clean_lines(
                get_function_contents_by_name(secondary_file_contents, "training_function")
            )
    _dl_line = "train_dataloader, eval_dataloader = get_dataloaders(accelerator, batch_size)\n"
    # Specific code in our script that differs from the full version, aka what is new
    new_feature_code = []
    passed_idxs = []  # We keep track of the idxs just in case it's a repeated statement
    it = iter(feature_file_func)
    for i in range(len(feature_file_func) - 1):
        if i not in passed_idxs:
            line = next(it)
            if (line not in full_file_func) and (line.lstrip() != _dl_line):
                if "TESTING_MOCKED_DATALOADERS" not in line:
                    new_feature_code.append(line)
                    passed_idxs.append(i)
                else:
                    # Skip over the `config['num_epochs'] = 2` statement
                    _ = next(it)
    # Extract out just the new parts from the full_file_training_func
    new_full_example_parts = []
    passed_idxs = []  # We keep track of the idxs just in case it's a repeated statement
    for i, line in enumerate(base_file_func):
        if i not in passed_idxs:
            if (line not in full_file_func) and (line.lstrip() != _dl_line):
                if "TESTING_MOCKED_DATALOADERS" not in line:
                    new_full_example_parts.append(line)
                    passed_idxs.append(i)
    # Finally, get the overall diff
    diff_from_example = [line for line in new_feature_code if line not in new_full_example_parts]
    if secondary_filename is not None:
        diff_from_two = [line for line in full_file_contents if line not in secondary_file_func]
        diff_from_example = [line for line in diff_from_example if line not in diff_from_two]
    return diff_from_example