It uses the PyCrypto package to generate random numbers. The Random class is a Fortuna generator seeded with 8 bytes from the system RNG, the PID, and time: https://github.com/dlitz/pycrypto/blob/master/lib/Crypto/Ran...
I doubt eight bytes is enough for cryptography...
If you need random bytes in Python, use os.urandom:
secret = os.urandom(32)
https://docs.python.org/2/library/os.html#os.urandom