I have been working on a python module to control a UC15 GSM/GPRS chip,
this chip have several functionalities:
- Sms
- Phone calls
- Http
- TCP/UDP Client
- etc.

So i would like to build a module for those instead of having everythin
in a huge script.

I would like to import just the functionslity i need in the test scripts,
maybe something like this:

from uc15 import uc15_sms

AFAIK this can be achieved defining a uc15_sms class in the uc15.py module

The UC15 is controlled via serial communication,, but i have trouble
knowing how to share the same serial port when working with more than one
functionality.

Proposal 1: Should i add a serial object as global in the uc15.py module
Proposal 2: Let the user pass the serial object when constructing the class
            objects, like so

from uc15 import UC15_Http
from uc15 import UC15_Sms

            my_serial = serial.Serial()
            my_http = UC15_Http(my_serial)
            my_Sms = UC15_Sms(my_serial)

Proposal 3: Just have a UC15 class with subclasses to represent each of the
            functionalities, like so:

from uc15 import UC15

            my_serial = serial.Serial()

            my_uc15 = UC15(my_serial)
            my_uc15.Sms.send_sms(phone, msg)