How to use the pdf2image.parsers.parse_buffer_to_ppm function in pdf2image

def _parse_format(fmt, grayscale=False):
    fmt = fmt.lower()
    if fmt[0] == ".":
        fmt = fmt[1:]
    if fmt in ("jpeg", "jpg"):
        return "jpeg", "jpg", parse_buffer_to_jpeg, False
    if fmt == "png":
        return "png", "png", parse_buffer_to_png, False
    if fmt in ("tif", "tiff"):
        return "tiff", "tif", None, True
    if fmt == "ppm" and grayscale:
        return "pgm", "pgm", parse_buffer_to_pgm, False
    # Unable to parse the format so we'll use the default
    return "ppm", "ppm", parse_buffer_to_ppm, False