Setting a foreign key as a nullable key in model file is not working in loopback 4

Describe the bug

I want to set up a field that is defined as a foreign key, but also supports the ability to be null. In the model file, I have this already

  @belongsTo(() => Bill, { keyTo: 'BillID', name: 'Bill' })
  BillID: Number;

But what I want to do is something like this

  @property({
    type: Number,
    required: false,
    jsonSchema: { nullable: true },
    mssql: { "columnName": "BillID", "dataType": "int", "dataPrecision": null, "dataScale": null, "nullable": "YES" },
  })
  @belongsTo(() => Bill, { keyTo: 'BillID', name: 'Bill' })
  BillID: Number;

but that does not work. How can I set this up?

Logs

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Additional information

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Reproduction

not needed as problem is obvious

L’issue identifie un fichier de modèle contenant les déclarations @property et @belongsTo pour BillID ; commencez par retracer la manière dont LoopBack 4 représente les clés étrangères nullable. La tâche sera considérée comme terminée lorsqu’une configuration prise en charge aura été confirmée ou qu’une modification nécessaire du framework aura été clarifiée, et que le comportement nullable de BillID aura été vérifié.