Difflib is a built-in module in the Python programming language consisting of different simple functions and classes that allow users to compare data sets. The module offers the outputs of these sequence comparisons in a format that can be read by a human, using deltas to show the differences more efficiently. The difflib module is generally used to compare the sequence of the strings. But we can also use it to compare other data types as long as they are hash-able. We know that an object is hash-able if its hash value does not alter through the duration of its lifetime.

The most commonly utilized classes in the Python difflib module are the Differ and the Sequence Matcher classes. There are also a few other helper classes and functions that can assist with more particular operations.