docs: def to_text(value, encoding='utf-8'):
      """Convert value to unicode, default encoding is utf-8
  
      :param value: Value to be converted
      :param encoding: Desired encoding
      """
      if not value:
          return ''
      if isinstance(value, six.text_type):
          return value
      if isinstance(value, six.binary_type):
          return value.decode(encoding)
      return six.text_type(value)