def daterange(self, datecol, date_start, op, **args):
        """
        Returns rows in a date range
        """
        df = self._daterange(datecol, date_start, op, **args)
        if df is None:
            self.err("Can not select date range data")
        self.df = df
def daterange ( self , datecol , date_start , op , ** args ) : df = self . _daterange ( datecol , date_start , op , ** args ) if df is None : self . err ( "Can not select date range data" ) self . df = df
Returns rows in a date range