#NEWLINE# def __init__( self , value , parent = None , key = None , depth = None ) : #NEWLINE# #INDENT# TreeNode . __init__ ( self , value , parent = parent , key = key , depth = depth ) #NEWLINE# self . _child_keys = None #NEWLINE# self . _children = { #NEWLINE# #INDENT# #NEWLINE# #UNINDENT# }