Read the file content and load it as JSON.

    Arguments:
      file_name (:py:class:`str`): The filename.

    Returns:
      :py:class:`dict`: The loaded JSON data.

    Raises:
      :py:class:`FileNotFoundError`: If the file is not found.

def _read_file(file_name):
    """Read the file content and load it as JSON.

    Arguments:
      file_name (:py:class:`str`): The filename.

    Returns:
      :py:class:`dict`: The loaded JSON data.

    Raises:
      :py:class:`FileNotFoundError`: If the file is not found.

    """
    with open(file_name) as config_file:
        data = json.load(config_file)
    return data