code: func isBIP0030Node(node *blockNode) bool {
  	if node.height == 91842 && node.hash.IsEqual(block91842Hash) {
  		return true
  	}
  
  	if node.height == 91880 && node.hash.IsEqual(block91880Hash) {
  		return true
  	}
  
  	return false
  }
docs: // isBIP0030Node returns whether or not the passed node represents one of the
  // two blocks that violate the BIP0030 rule which prevents transactions from
  // overwriting old ones.