def create_string(self, value: str) -> String:
        """
        Creates a new :class:`ConstantString`, adding it to the pool and
        returning it.

        :param value: The value of the new string as a UTF8 string.
        """
        self.append((
            8,
            self.create_utf8(value).index
        ))
        return self.get(self.raw_count - 1)