code: def set_ext_params(ext_key, ext_params)
        raise ArgumentError unless ext_params.is_a?(Hash)
        @extensions[ext_key] = ext_params
      end
docs: Set the extension parameters for a specific vendor
  
   @param ext_key [String] The identifier for the vendor-specific parameters
   @param ext_params [Hash] The parameters, this is allowed to be two-levels deep