PyMOTW: uuid

RFC 4122 defines a system for creating universally unique identifiers for resources in a way that does not require a central registrar. UUID values are 128 bits long and “can guarantee uniqueness across space and time”. They are useful for ids for documents, hosts, application clients, and other situations where a unique value is necessary. The RFC is specifically geared toward creating a Uniform Resource Name namespace.

Read more at pymotw.com: uuid