i would like to get a program in python that says that the 2 text files are nearly duplicate.

Means:
some text files are having same data but not exactly duplicate. part of it is same content. i want to know that the second file is 10% duplicate, 30% duplicate and so on to the first file.

can we use SequenceMatcher in difflib.py?

pls reply me if u have any idea or how to do it or any program?