I found the section on ordering categorical features really interesting,
but the A, B, C example seemed inconsistent. Am I interpreting this passage
wrong, or are there typos? Aren't the split candidates A  C, B and A, C 
B ?
For example, for a binary classification problem with one categorical
feature with three categories A, B and C with corresponding proportion of
label 1 as 0.2, 0.6 and 0.4, the categorical features are ordered as A
followed by C followed B or A, B, C. The two split candidates are A  C, B
and A , B  C where  denotes the split.
