'it also present a dictionary like interface
:param db key value database
:root: blank or trie node in form of [key, value] or [v0,v1..v15,v]'

def __init__(self, db, root_hash=BLANK_ROOT, transient=False):

    self.db = db
    self.transient = transient
    if self.transient:
        self.update = self.get = self.delete = transient_trie_exception
    self.set_root_hash(root_hash)
    self.death_row_timeout = 5000
    self.nodes_for_death_row = []
    self.journal = []
