code: private int indexOf(List<Block> targetBlocks, Block block)
      {
          int pos = 0;
          for (Block targetBlock : targetBlocks) {
              // Test a non deep equality
              if (blockEquals(targetBlock, block)) {
                  return pos;
              }
              pos++;
          }
          return -1;
      }
docs: Shallow indexOf implementation that only compares nodes based on their data and not their children data.
  
  @param targetBlocks the list of blocks to look into
  @param block the block to look for in the list of passed blocks
  @return the position of the block in the list of target blocks and -1 if not found