code: def _unicode(value):
      
      if isinstance(value, _TO_UNICODE_TYPES):
          return value
      if not isinstance(value, bytes_type):
          raise TypeError(
              "Expected bytes, unicode, or None; got %r" % type(value)
          )
      return value.decode("utf-8")
docs: Converts a string argument to a unicode string.
  
      If the argument is already a unicode string or None, it is returned
      unchanged.  Otherwise it must be a byte string and is decoded as utf8.