class MaxFileSizeValidator extends FileValidator {
  buildErrorMessage(file?: IFile): string
  isValid(file?: IFile): boolean

  // inherited from nest/packages/common/FileValidator
  constructor(validationOptions: TValidationOptions)
  protected validationOptions: TValidationOptions
  abstract isValid(file?: TFile | TFile[] | Record<string, TFile[]>): boolean | Promise<boolean>
  abstract buildErrorMessage(file: any): string
}

buildErrorMessage(file?: IFile): string

isValid(file?: IFile): boolean