[Discuss-gnuradio] Quetion regarding crc checks .

Dear all,
    I am currently working on a gnuradio project and i was wondering if anybody could please share some information about how crc checks are made. As in when one makes a crc32 call from ones python script , in crc.py it says the following

crc = digital_swig.crc32(s)

and there after it makes a call to _digital_swig.crc32. I dont fully understand the "behind the scene operation" of "_digital_swig" . I understand that its a library associated file but its operation is what i cannot fully comprehend. Does it help make a call to digital_crc32.cc file which has all the underlying code.

I would be awfully obliged if somebody were to spare sometime and help out in this regard.

Thanks,
Anay.