def get_num_frames_in_event(event):
    """
    Gets the number of frames in an event retrieved from Pilatus files (or HiDRA).

    For the Pilatus detector, an event corresponds to the content of a single CBF data
    file. Since the Pilatus detector writes one frame per file, this function always
    returns 1.

    NOTE: This function is designed to be injected as a member function into an
    :class:`~onda.utils.data_event.DataEvent` object.

    Arguments:

        event (:class:`~onda.utils.data_event.DataEvent`): an object storing the event
            data.

    Returns:

        int: the number of frames in the event.
    """
    del event
    return 1
