I have a .net class library which uses NSwag to generate client code from an OpenApi spec, a portion of which is as follows:

"postal_code": {
    "anyOf": [
        {
            "type": "string"
        },
        {
            "type": "null"
        }
    ],
    "title": "Postal Code"
},

…and when the client code is generated it produces the following type

public partial class Postal_code
{

    private System.Collections.Generic.IDictionary<string, object> _additionalProperties;

    [Newtonsoft.Json.JsonExtensionData]
    public System.Collections.Generic.IDictionary<string, object> AdditionalProperties
    {
        get { return _additionalProperties ?? (_additionalProperties = new System.Collections.Generic.Dictionary<string, object>()); }
        set { _additionalProperties = value; }
    }

}

Which is not what I want, I just want Postal_Code to be represented as a nullable string.

My current config is as below, is there an option I can add to achieve what I’m looking for?

<ItemGroup>
  <OpenApiReference Include="OpenApisOpenApiSpec.json" CodeGenerator="NSwagCSharp" Options="/ClientClassAccessModifier:internal" ClassName="NSwagGeneratedClient" />
</ItemGroup>