code: def unicode(self, s, encoding=None):
          
          if isinstance(s, unicode):
              return unicode(s)
  
          return self.to_unicode(s, encoding)
docs: Convert a string to unicode using the given encoding, and return it.
  
          This function uses the underlying to_unicode attribute.
  
          Arguments:
  
            s: a basestring instance to convert to unicode.  Unlike Python's
              built-in unicode() function, it is okay to pass unicode strings
              to this function.  (Passing a unicode string to Python's unicode()
              with the encoding argument throws the error, "TypeError: decoding
              Unicode is not supported.")
  
            encoding: the encoding to pass to the to_unicode attribute.
              Defaults to None.