Wrong to scan .ts file

[cyw3]

python3.7.0 lizard 1.17.5

$ python lizard.py --csv --sort cyclomatic_complexity --CCN 20 --working_threads 8 -l typescript test.ts

And output nothing.

export abstract class BaseType {
  required (): RequiredType<this> {
    return result
  }

  forbidden (): never {
    return this as any as never
  }

  options (options: Joi.ValidationOptions) {
    return this
  }

  strict (isStrict?: boolean) {
    return this
  }

  default (value: any) {
    return this
  }

  error (err: Error | Joi.ValidationErrorFunction) {
    return this
  }

  nullable (): UnionType<this, ConstType<null>> {
    return this as any
  }
}