Question 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.