[web2py] referencing request, session from module folder

[kawate]

hello ;

i put my module in application/modules folder.
i assumed that session, request is global, but referencing session and
request cause undefined name error.
currently i pass these as parameters, so far it works as i expected.

But teach me how to make global environment available to my module.

I tried,

in models/db.py
who = mymodules.Who(globals())

in mymodule

class Who(object):
    def __init__(self,environment): #,session,request):
       self.environment = environment
        request = environment['request']
        session = environment['session']
        ....
        .....
  def login(......)
        request = environment['request']
        session = environment['session']
        ....

__init__ works OK
but when i call login, i get error as

Traceback (most recent call last):
  File "/Users/kawateyutaka/project3/web2py/gluon/main.py", line 477,
in wsgibase
    session._try_store_on_disk(request, response)
  File "/Users/kawateyutaka/project3/web2py/gluon/globals.py", line
401, in _try_store_on_disk
    cPickle.dump(dict(self), response.session_file)
TypeError: expected string or Unicode object, NoneType found