Prevent resizing a view controller which is presented as a sheet (swift 4.0, cocoa in macOS)

SomeSheetViewController.swift

class  SomeSheetViewController.swift {
  ...
  
  override func viewDidLoad() {
    ...
    
    // referenced by https://stackoverflow.com/a/30112516/6770674
    self.preferredContentSize = self.view.frame.size
    
    ...
  }
  
  ...
}