'Use this method to upload a .png file with a sticker for later use in createNewStickerSet and addStickerToSet
methods (can be used multiple times). Returns the uploaded File on success.
:param user_id:
:param png_sticker:
:return:'

def upload_sticker_file(self, user_id, png_sticker):

    result = apihelper.upload_sticker_file(self.token, user_id, png_sticker)
    return types.File.de_json(result)
