[Bug] Any of property is not defined swift file

[Dayzen]

I use this generator by my open API.
But some errors appeared in my generated swift files.

If my open API spec included anyOf property then APIModel is not created
Am i missing some right flow?

command: swaggen generate ${my open API url}

xcode version 12.2
mac os: 10.15.7
Apple Swift version 5.3.1 (swiftlang-1200.0.41 clang-1200.0.32.8)
Target: x86_64-apple-darwin19.6.0

Open API spec

operator: {
  anyOf: [
    {
      type: "null"
    },
  ]
}

Appeared error