code: def is_quoted(value):
      '''
      Return a single or double quote, if a string is wrapped in extra quotes.
      Otherwise return an empty string.
      '''
      ret = ''
      if isinstance(value, six.string_types) \
              and value[0] == value[-1] \
              and value.startswith(('\'', '"')):
          ret = value[0]
      return ref is_quoted(value):
      '''
      Return a single or double quote, if a string is wrapped in extra quotes.
      Otherwise return an empty string.
      '''
      ret = ''
      if isinstance(value, six.string_types) \
              and value[0] == value[-1] \
              and value.startswith(('\'', '"')):
          ret = value[0]
      return ret
docs: Return a single or double quote, if a string is wrapped in extra quotes.
      Otherwise return an empty string.