def METHOD_NAME(image_path, header_path, hdu=0, **kwargs):
    """
    Convert a FITS file containing an image and a header
    to a plaintext file containing only the string representation
    of the header.
    This is to be used in the context of generating header-only test data
    files.
    Parameters
    -----------
    image_path : path-like
        Path to original image data FITS file
    header_path : path-like
        Path to header-only test data plaintext file
    hdu : `int`, optional
        HDU index of the header to write the header for
    Additional Parameters
    ---------------------
    Keyword arguments accepted by `~astropy.io.fits.Header.totextfile`
    See Also
    --------
    get_dummy_map_from_header
    """
    with astropy.io.fits.open(image_path) as hdul:
        hdul[hdu].header.totextfile(header_path, **kwargs)