code: def encoding(self):
          
          if self.redirect is not None:
              return self.redirect.encoding
          else:
              return super(TeeStringIO, self).encoding
docs: Gets the encoding of the `redirect` IO object
  
          Doctest:
              >>> redirect = io.StringIO()
              >>> assert TeeStringIO(redirect).encoding is None
              >>> assert TeeStringIO(None).encoding is None
              >>> assert TeeStringIO(sys.stdout).encoding is sys.stdout.encoding
              >>> redirect = io.TextIOWrapper(io.StringIO())
              >>> assert TeeStringIO(redirect).encoding is redirect.encoding