return the first non-None setting from a series where each
        element in `sec_param_list` is a section, param pair suitable for
        a get_config_setting call.

        Note that non-None values for overrides for this ConfigWrapper instance will cause
            this call to only evaluate the first element in the cascade.

def get_from_config_setting_cascade(self, sec_param_list, default=None, warn_on_none_level=logging.WARN):
        """return the first non-None setting from a series where each
        element in `sec_param_list` is a section, param pair suitable for
        a get_config_setting call.

        Note that non-None values for overrides for this ConfigWrapper instance will cause
            this call to only evaluate the first element in the cascade.
        """
        for section, param in sec_param_list:
            r = self.get_config_setting(section, param, default=None, warn_on_none_level=None)
            if r is not None:
                return r
        section, param = sec_param_list[-1]
        if default is None:
            _warn_missing_setting(section, param, self._config_filename, warn_on_none_level)
        return default