How to extract, clear and refill the entropy pool from a USB hardware RNG?

Is there a programming method to permit the extraction of entropy bits from the entropy pool using standard python programming calls, so that they are replenished from a USB hardware RNG?

with open("/dev/random",'rb') as dr:
    b = dr.read(num_bytes)

Any help on this would be appreciated.

Please respect that this is a question about how to get and refresh entropy bits, not a solicitation for opinions about the cryptographic sufficiency of a fixed 256 bit entropy pool.