def self.cloudtrail(region: MU.curRegion, credentials: nil)
        region ||= myRegion
        @@cloudtrail_api[credentials] ||= {}
        @@cloudtrail_api[credentials][region] ||= MU::Cloud::AWS::AmazonEndpoint.new(api: "CloudTrail", region: region, credentials: credentials)
        @@cloudtrail_api[credentials][region]