code: @SuppressWarnings("unchecked")
      public static List<HierarchicalConfiguration> getConfigurationsAt(HierarchicalConfiguration config,
                                                                        String key) throws
          DeployerConfigurationException {
          try {
              return config.configurationsAt(key);
          } catch (Exception e) {
              throw new DeployerConfigurationException("Failed to retrieve sub-configurations at '" + key + "'", e);
          }
      }
docs: Returns the sub-configuration tree whose root is the specified key.
  
  @param config the configuration
  @param key    the key of the configuration tree
  @return the sub-configuration tree, or null if not found
  @throws DeployerConfigurationException if an error occurs