Distributed mutual exclusion is a fundamental problem in distributed systems since resources are shared and exclusive access to these resources are needed as in a single-node computer system. Algorithms for this purpose may be broadly classified as permission-based or token-based algorithms. A process needs to obtain permission from all other processes to enter its critical section in the former method and the possession of a token entitles a process to enter its CS in the latter method. In this chapter, we review fundamental permission-based and token-based algorithms for distributed mutual exclusion and implement them in Python using mpi4py.