For some reason, the 
block has inconsistent behaviour. When you call it with one block, such as 
, the result is only one-dimensional. This is inconsistent with the two-dimensional result when multiple blocks are split, e.g. 
, and this could prove problematic in certain codebases, such as if you're trying to find the length of a block of code with 
.
You just have to check other characteristics of the resulting lists before proceeding
I've done a reasonable amount of block splitting and recombining and never encountered a real problem with this behaviour