code: def file_field(*args, **kwargs):
      '''
      File field
      '''
      file_field = wtforms.FileField(*args, **kwargs)
      file_field.input_type = 'file_field'
      return file_fielf file_field(*args, **kwargs):
      '''
      File field
      '''
      file_field = wtforms.FileField(*args, **kwargs)
      file_field.input_type = 'file_field'
      return file_field
docs: File field