formsToKeep: For example, if formsToKeep is ["purchase", "foobar"], then submissions["purchase"] and submissions["foobar"] will not be cleared, but the rest will. If formsToKeep is empty, then all will be cleared.
See Implementation
formsToKeep: For example, if formsToKeep is ["purchase", "foobar"], then submissions["purchase"] and submissions["foobar"] will not be cleared, but the rest will. If formsToKeep is empty, then all will be cleared.