docs: def file_save(self, name, filename=None, folder="", keep_ext=True) -> bool:
          """ Easy save of a file """
          if name in self.files:
              file_object = self.files[name]
              clean_filename = secure_filename(file_object.filename)
              if filename is not None and keep_ext:
                  clean_filename = filename + ".%s" % \
                      (clean_filename.rsplit('.', 1)[1].lower())
              elif filename is not None and not keep_ext:
                  clean_filename = filename
              file_object.save(os.path.join(
                  current_app.config['UPLOADS']['FOLDER'],
                  folder, clean_filename))
          return None