code: private static InstanceContext parseContext(JsonObject config) {
      JsonObject context = config.getObject("__context__");
      if (context == null) {
        throw new IllegalArgumentException("No component context found.");
      }
      config.removeField("__context__");
      return Contexts.deserialize(context);
    }
docs: Parses an instance context from configuration.
  
  @param config The verticle configuration.
  @return The verticle context.