### Question:
BlockUtils { public static boolean blockInSomeBlockChain(Block block, Blockchain blockChain) { return blockInSomeBlockChain(block.getHash(), block.getNumber(), blockChain); } private  BlockUtils(); static boolean blockInSomeBlockChain(Block block, Blockchain blockChain); static Set<Keccak256> unknownDirectAncestorsHashes(Block block, Blockchain blockChain, BlockStore store); static Set<Keccak256> unknownAncestorsHashes(Keccak256 blockHash, Blockchain blockChain, BlockStore store); static Set<Keccak256> unknownAncestorsHashes(Set<Keccak256> hashesToProcess, Blockchain blockChain, BlockStore store, boolean withUncles); static void addBlockToList(List<Block> blocks, Block block); static List<Block> sortBlocksByNumber(List<Block> blocks);  }### Answer:
@Test public void blockInSomeBlockChain() { BlockChainImpl blockChain = new BlockChainBuilder().build(); Block genesis = new BlockGenerator().getGenesisBlock(); genesis.setStateRoot(blockChain.getRepository().getRoot()); genesis.flushRLP(); Block block1 = new BlockBuilder().parent(genesis).build(); Block block1b = new BlockBuilder().parent(genesis).build(); Block block2 = new BlockBuilder().parent(block1).build(); Block block3 = new BlockBuilder().parent(block2).build(); blockChain.getBlockStore().saveBlock(block3, new BlockDifficulty(BigInteger.ONE), false); Assert.assertEquals(ImportResult.IMPORTED_BEST, blockChain.tryToConnect(genesis)); blockChain.tryToConnect(block1); blockChain.tryToConnect(block1b); Assert.assertTrue(BlockUtils.blockInSomeBlockChain(genesis, blockChain)); Assert.assertTrue(BlockUtils.blockInSomeBlockChain(block1, blockChain)); Assert.assertTrue(BlockUtils.blockInSomeBlockChain(block1b, blockChain)); Assert.assertFalse(BlockUtils.blockInSomeBlockChain(block2, blockChain)); Assert.assertTrue(BlockUtils.blockInSomeBlockChain(block3, blockChain)); }