How to use the afdko.ufotools.validateLayers function in afdko

def open(self, use_hash_map):
        font_path = self.font_path

        if self.font_format == 'UFO':
            self.font_type = UFO_FONT_TYPE
            ufotools.validateLayers(font_path)
            self.defcon_font = defcon.Font(font_path)
            self.ufo_format = self.defcon_font.ufoFormatVersion
            if self.ufo_format < 2:
                self.ufo_format = 2
            self.use_hash_map = use_hash_map
            self.ufo_font_hash_data = ufotools.UFOFontData(
                font_path, self.use_hash_map,
                programName=ufotools.kCheckOutlineName)
            self.ufo_font_hash_data.readHashMap()

        else:
            print("Converting to temp UFO font...")
            self.temp_ufo_path = temp_path = get_temp_dir_path('font.ufo')

            if not run_shell_command([
                    'tx', '-ufo', font_path, temp_path]):

normalizeUFO(instancePath, outputPath=None, onlyModified=True,
                         writeModTimes=False)

    if options.doAutoHint or options.doOverlapRemoval:
        logger.info("Applying post-processing...")
        # Apply autohint and checkoutlines, if requested.
        for instancePath in newInstancesList:
            # make new instance font.
            updateInstance(instancePath, options)

    # checkoutlinesufo does ufotools.validateLayers()
    if not options.doOverlapRemoval:
        for instancePath in newInstancesList:
            # make sure that there are no old glyphs left in the
            # processed glyphs folder
            validateLayers(instancePath)

    # The defcon library renames glyphs. Need to fix them again
    if options.doOverlapRemoval or options.doAutoHint:
        for instancePath in newInstancesList:
            if options.doNormalize:
                normalizeUFO(instancePath, outputPath=None, onlyModified=False,
                             writeModTimes=False)

    # Restore the contents of the instances' 'features.fea' files
    for fea_pth, fea_cntnts in features_store.items():
        with open(fea_pth, 'w') as fp:
            fp.write(fea_cntnts)

for contour in fixed_glyph:
                    for point in contour:
                        point.x = int(round(point.x))
                        point.y = int(round(point.y))
            restore_contour_order(fixed_glyph, original_contours)
        # The following is needed when the script is called from another
        # script with Popen():
        sys.stdout.flush()
    # update layer plist: the hash check call may have deleted processed layer
    # glyphs because the default layer glyph is newer.

    # At this point, we may have deleted glyphs in the
    # processed layer.writer.getGlyphSet()
    # will fail unless we update the contents.plist file to match.
    if options.allow_changes:
        ufotools.validateLayers(font_path, False)

    if not font_changed:
        # Even if the program didn't change any glyphs,
        # we should still save updates to the src glyph hash file.
        font_file.close()
    else:
        font_file.save()

    if processed_glyph_count != seen_glyph_count:
        print("Skipped %s of %s glyphs." %
              (seen_glyph_count - processed_glyph_count, seen_glyph_count))
    if not options.quiet_mode:
        print("Done with font")