Get a part of the file, from start byte to end byte (integers)

def readpartial(self, start, end):
        'Get a part of the file, from start byte to end byte (integers)'
        #return self.jfs.raw('%s?mode=bin' % self.path,
        return self.jfs.raw(url=self.path, params={'mode':'bin'},
                            # note that we deduct 1 from end because
                            # in http Range requests, the end value is included in the slice,
                            # whereas in python, it is not
                            extra_headers={'Range':'bytes=%s-%s' % (start, end-1)})