def wf_alert_severity?(severity)
      return true if %w[INFO SMOKE WARN SEVERE].include?(severity)
      raise Wavefront::Exception::InvalidAlertSeverity
    end
def wf_alert_severity?(severity)
      return true if %w[INFO SMOKE WARN SEVERE].include?(severity)
      raise Wavefront::Exception::InvalidAlertSeverity
    end
Ensure the given argument is a valid alert severity

 @param severity [String] severity
 @return true if valid
 @raise Wavefront::Exceptions::InvalidAlertSeverity if not valid