import difflib
class PatchGenerator:
    @staticmethod
    def unified_diff(a,b,filename='file'):
        return ''.join(difflib.unified_diff(a.splitlines(True),b.splitlines(True),fromfile=filename,tofile=filename+'.refactored'))
    @staticmethod
    def summarize_patch(d,maxl=20):
        return '\n'.join(d.splitlines()[:maxl])