Whenever I have lists or tuple lists I have something like u' (check sample result). What does this do?

(u'03/02/2009', u'Billing for gas', 100.0, 210.0, 200.0)
(u'15/04/2009', u'paying fees for OUT', 0.0, 10405.0, 0.0)
(u'03/02/2009', u'Billing for gas', 100.0, 210.0, 200.0)