implicitly return nil instead of returning an empty string if a schema attribute doesn't have a corresponding method on the event record or the export class
implicitly return nil instead of returning an empty string if a schema attribute doesn't have a corresponding method on the event record or the export class

UM-USElab/gradecraft-development,UM-USElab/gradecraft-development,UM-USElab/gradecraft-development,UM-USElab/gradecraft-development