Get :class:`rtcclient.models.Severity` object by its name

        At least either of `projectarea_id` and `projectarea_name` is given

        :param severity_name: the severity name
        :param projectarea_id: the :class:`rtcclient.project_area.ProjectArea`
            id
        :param projectarea_name: the project area name
        :return: the :class:`rtcclient.models.Severity` object
        :rtype: rtcclient.models.Severity

def getSeverity(self, severity_name, projectarea_id=None,
                    projectarea_name=None):
        """Get :class:`rtcclient.models.Severity` object by its name

        At least either of `projectarea_id` and `projectarea_name` is given

        :param severity_name: the severity name
        :param projectarea_id: the :class:`rtcclient.project_area.ProjectArea`
            id
        :param projectarea_name: the project area name
        :return: the :class:`rtcclient.models.Severity` object
        :rtype: rtcclient.models.Severity
        """

        self.log.debug("Try to get <Severity %s>", severity_name)
        if not isinstance(severity_name,
                          six.string_types) or not severity_name:
            excp_msg = "Please specify a valid Severity name"
            self.log.error(excp_msg)
            raise exception.BadValue(excp_msg)

        severities = self._getSeverities(projectarea_id=projectarea_id,
                                         projectarea_name=projectarea_name,
                                         severity_name=severity_name)

        if severities is not None:
            severity = severities[0]
            self.log.info("Find <Severity %s>", severity)
            return severity

        self.log.error("No Severity named %s", severity_name)
        raise exception.NotFound("No Severity named %s" % severity_name)