def _convert_char_to_type(self, type_char):
        """
        Ensures a read character is a typecode.

        :param type_char: Read typecode
        :return: The typecode as a string (using chr)
        :raise RuntimeError: Unknown typecode
        """
        typecode = type_char
        if type(type_char) is int:
            typecode = chr(type_char)

        if typecode in self.TYPECODES_LIST:
            return typecode
        else:
            raise RuntimeError(
                "Typecode {0} ({1}) isn't supported.".format(type_char, typecode)
            )
Ensures a read character is a typecode.

        :param type_char: Read typecode
        :return: The typecode as a string (using chr)
        :raise RuntimeError: Unknown typecode