Removal of has_keys_with_prefix Method

[Amerikranian]

Hi,

I was looking through the source and saw that has_keys_with_prefix is deprecated and will be removed. Could you elaborate as to why? This seems very useful for if you wanted to fetch a random word of given length from the trie (I myself just so happen to need to do this). Using iterkeys is unacceptable, as it is too slow and gives extraneous information--I only want to know if the given prefix forms a valid path through a tree.