code: @Nonnull
      public DeploymentNode addDeploymentNode(@Nullable String environment, @Nonnull String name, @Nullable String description, @Nullable String technology) {
          return addDeploymentNode(environment, name, description, technology, 1);
      }
docs: Adds a top-level deployment node to this model.
  
  @param environment   the name of the deployment environment
  @param name          the name of the deployment node
  @param description   the description of the deployment node
  @param technology    the technology associated with the deployment node
  @return a DeploymentNode instance
  @throws IllegalArgumentException if the name is not specified, or a top-level deployment node with the same name already exists in the model