public static RequestEntityConfigBuilder <TRequest, TEntity> UseKeys <TRequest, TEntity, TItemKey, TEntityKey>(
     this RequestEntityConfigBuilder <TRequest, TEntity> config,
     Expression <Func <TRequest, TItemKey> > requestKeyExpr,
     Expression <Func <TEntity, TEntityKey> > entityKeyExpr)
     where TEntity : class
 {
     return(config
            .UseEntityKey(entityKeyExpr)
            .UseRequestKey(requestKeyExpr));
 }
 public static RequestEntityConfigBuilder <TRequest, TEntity> UseKeys <TRequest, TEntity>(
     this RequestEntityConfigBuilder <TRequest, TEntity> config,
     string[] requestKeyMembers,
     string[] entityKeyMembers)
     where TEntity : class
 {
     return(config
            .UseEntityKey(entityKeyMembers)
            .UseRequestKey(requestKeyMembers));
 }