code: private void modifyTenantProperties(TenantDefinition oldTenantDef, TenantDefinition newTenantDef) {
          // _CreatedOn must be the same. _ModifiedOn must be updated.
          newTenantDef.setProperty(CREATED_ON_PROP, oldTenantDef.getProperty(CREATED_ON_PROP));
          newTenantDef.setProperty(MODIFIED_ON_PROP, Utils.formatDate(new Date().getTime()));
      }
docs: Set required properties in a new Tenant Definition.
  
  @param   oldTenantDef  Old {@link TenantDefinition}.
  @param   newTenantDef  New {@link TenantDefinition}.