Converts the report_generators list to a dictionary, and caches the result.
        :return: A dictionary with such references.

def get_reporters(self):
        """
        Converts the report_generators list to a dictionary, and caches the result.
        :return: A dictionary with such references.
        """

        if not hasattr(self, '_report_generators_by_key'):
            self._report_generators_by_key = {r.key: r for r in self.report_generators}
        return self._report_generators_by_key