code: public V get(ResourceType type, String poolGroupName) {
      Map<String, V> poolGroupNameMap = typePoolGroupNameMap.get(type);
      if (poolGroupNameMap == null) {
        return null;
      }
      return poolGroupNameMap.get(poolGroupName);
    }
docs: Get the value with the appropriate keys
  
  @param type Resource type
  @param poolGroup Name of pool group
  @param value Value to put
  @return Previous value, can be null if if wasn't set