private <K, V, WCT extends WriteCommand> MVCCEntry<K, V> acquireKeyFromContext(InvocationContext ctx, WCT command, Object key,
         TriPredicate<? super WCT, Object, MVCCEntry<?, ?>> commandKeyPredicate) {
      //noinspection unchecked
      MVCCEntry<K, V> entry = (MVCCEntry<K, V>) ctx.lookupEntry(key);
      if (commandKeyPredicate != null && !commandKeyPredicate.test(command, key, entry) || !entry.isChanged()) {
         return null;
      }
      return entry;
   }