Naive question

[Duncan Smith]

I run the following script (Test2.py), query f.id at the command-line prompt
and get NameError: f.


def start():
    f = Forest()


class Forest:
    def __init__(self):
        self.name = 'Forest'
        self.id = 1
        self.graphs = []
        self.count = 0
        self.d = DiGraph('initial', self)

class DiGraph:
    def __init__(self, label, pForest):
        self.owner = pForest
        self.name = label
        self.id = pForest.count
        pForest.graphs.append(self.id)
        pForest.count = pForest.count + 1


>>> from Test2 import *
>>> start()
>>> f.id
Traceback (innermost last):
  File "<interactive input>", line 1, in ?
NameError: f
>>>


If I comment out the first two lines and create the Forest instance at the
command line, then I can query f.id etc.


#def start():
#    f = Forest()


class Forest:
    def __init__(self):
        self.name = 'Forest'
        self.id = 1
        self.graphs = []
        self.count = 0
        self.d = DiGraph('initial', self)

class DiGraph:
    def __init__(self, label, pForest):
        self.owner = pForest
        self.name = label
        self.id = pForest.count
        pForest.graphs.append(self.id)
        pForest.count = pForest.count + 1

>>> from Test2 import *
>>> f=Forest()
>>> f.id
1
>>> f.d.owner.id
1
>>>


How can I achieve this without creating the Forest instance at the command
line?  Cheers.  Any help appreciated.

Duncan