How readable is this?

ConvertTableToTree.py

entries = getListOfTableEntriesSomeWhere()
entryTree = MyTree(entries)

################################

def group_entries(groupclass, entries, keyfunc):
    return [groupclass(k,g) for k,g in itertools.groupby(entries,keyfunc)]

key_sys    = lambda x: x.sys
key_subsys = lambda x: x.subsys
key_var    = lambda x: x.var
key_all    = lambda x: (x.sys, x.subsys, x.var)

class MyTree:
    def __init__(self, entries):
        self.entries = sorted(entries, key=key_all)
        self.name = name
        self.systems = group_entries(MySys, self.entries, key_sys)

class MySys:
    def __init__(self, name, entries):
        self.name = name
        self.subsystems = group_entries(MySubsys, entries, key_subsys)

class MySubsys:
    def __init__(self, name, entries):
        self.name = name
        self.variables = group_entries(MyVar, entries, key_var)

class MyVar:
    def __init__(self, name, entries):
        self.name = name
        self.entries = list(entries)

Using map at least provides a better idea of what's going on:

entries = getListOfTableEntriesSomeWhere()
entryTree = MyTree(entries)

################################

key_sys    = lambda x: x.sys
key_subsys = lambda x: x.subsys
key_var    = lambda x: x.var
key_all    = lambda x: (x.sys, x.subsys, x.var)

class MyTree:
    def __init__(self, entries):
        self.entries = sorted(entries, key=key_all)
        self.name = name
        self.systems = map(MySys, itertools.groupby(self.entries, key_sys))

class MySys:
    def __init__(self, name, entries):
        self.name = name
        self.subsystems = map(MySubsys,  itertools.groupby(entries, key_subsys))

class MySubsys:
    def __init__(self, name, entries):
        self.name = name
        self.variables = map(MyVar, itertools.groupby(entries, key_var))

class MyVar:
    def __init__(self, name, entries):
        self.name = name
        self.entries = list(entries)

Yeah, I like that better actually. Got rid of the indirection. Thanks.