code: protected boolean removeFromAttributeValueMapByKeys(final String... keys) {
  
          final Collection<AbstractHtml5SharedObject> sharedObjects = getSharedObjects();
          boolean listenerInvoked = false;
          final Collection<WriteLock> writeLocks = lockAndGetWriteLocks();
          boolean result = false;
          try {
  
              final Map<String, String> valueMap = getAttributeValueMap();
  
              if (nullableAttrValueMapValue) {
                  for (final String key : keys) {
                      result = valueMap.containsKey(key);
                      if (result) {
                          break;
                      }
                  }
              }
  
              for (final String key : keys) {
                  final String previous = valueMap.remove(key);
                  if (previous != null) {
                      result = true;
                  }
              }
  
              if (result) {
                  setModified(true);
                  invokeValueChangeListeners(sharedObjects);
                  listenerInvoked = true;
              }
  
          } finally {
              for (final Lock lock : writeLocks) {
                  lock.unlock();
              }
          }
          pushQueues(sharedObjects, listenerInvoked);
          return result;
      }
docs: removes the key value for the input key.
  
  @param keys
  @since 3.0.1
  @author WFF
  @return true if any of the given keys (as well as value contained
  corresponding to it) has been removed.