Samir’s answer is correct but somewhat cryptic. Basically, the salt is just a randomly derived bit of data that you prefix or postfix your data with to dramatically increase the complexity of a dictionary attack on your hashed value. So given a salt s and data d you’d just do the following to generate a salted hash of the data:
import hashlib
hashlib.sha512( s + d ).hexdigest()
See this wikipedia article for more details