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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def get_date_bounds(self):
 """ Return the upper and lower bounds along with operators that are needed to do an 'in range' test. Useful for SQL commands. Returns ------- tuple: (`str`, `date`, `str`, `date`) (date_gt, start, date_lt, end) e.g.: ('>=', start_date, '<', end_date) """

        start = end = None
        date_gt = '>='
        date_lt = '<='
        if self:
            if self.start:
                start = self.start
            if self.end:
                end = self.end
            if self.startopen:
                date_gt = '>'
            if self.endopen:
                date_lt = '<'

        return date_gt, start, date_lt, end