code: public DeploymentView createDeploymentView(SoftwareSystem softwareSystem, String key, String description) {
          assertThatTheSoftwareSystemIsNotNull(softwareSystem);
          assertThatTheViewKeyIsSpecifiedAndUnique(key);
  
          DeploymentView view = new DeploymentView(softwareSystem, key, description);
          view.setViewSet(this);
          deploymentViews.add(view);
          return view;
      }
docs: Creates a deployment view, where the scope of the view is the specified software system.
  
  @param softwareSystem    the SoftwareSystem object representing the scope of the view
  @param key               the key for the deployment view (must be unique)
  @param description       a description of the view
  @return                  a DeploymentView object
  @throws                  IllegalArgumentException if the software system is null or the key is not unique