python-automata is a well-documented Python library for working with DFAs, including the following features:

Basics

• simulate DFA execution input-by-input or over an iterable sequence
• validate a DFA's definition
• delta is a function, not a transition table
• check if the DFA's language is finite

Unary operations

• negation
• classical minimization
• DFCA minimization

Binary operations

• generalized cross-product construction, including DFA union, intersection, and symmetric difference

Constructing automata

• Make a randomly connected automaton of any size
• Make an automaton recognizing a given list of words

And more...

• Python 3 patch thanks to Kai Ruemmler: http://pastebin.com/RSHihyKL
• Contact the author: andrewbadr @ gmail
• You should use the SVN version, not the download.