def _decodeValues(self, values):
        """
        Decode a L{list} of header values into a L{list} of Unicode strings.

        @param values: A list of HTTP header values.
        @type values: L{list} of UTF-8 encoded L{bytes}

        @return: C{values}, with each item decoded
        @rtype: L{list} of L{unicode}
        """
        newValues = []

        for value in values:
            newValues.append(value.decode('utf8'))
        return newValues

        Decode a L{list} of header values into a L{list} of Unicode strings.

        @param values: A list of HTTP header values.
        @type values: L{list} of UTF-8 encoded L{bytes}

        @return: C{values}, with each item decoded
        @rtype: L{list} of L{unicode}
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/web/http_headers.py