def load(file)
      if file.nil? || !File.exist?(file)
        raise "Can't open #{file}."
      end
      loader = ReVIEW::YAMLLoader.new
      merge_config(@config.deep_merge(loader.load_file(file)))
    end
def load(file)
      if file.nil? || !File.exist?(file)
        raise "Can't open #{file}."
      end
      loader = ReVIEW::YAMLLoader.new
      merge_config(@config.deep_merge(loader.load_file(file)))
    end
Take YAML +file+ and update parameter hash.