<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def toString(self):
 """ Returns date as string. """

        slist = self.toList()
        sign = '' if slist[0] == '+' else '-'
        string = '/'.join(['%02d' % v for v in slist[1:]])
        return sign + string