def set_item(self, key, value):
        """
        Sets the item by key, and refills the table sorted.
        """
        keys = list(self.keys())

        # if it exists, update
        if key in keys:
            self.set_value(1,keys.index(key),str(value))

        # otherwise we have to add an element
        else:
            self.set_value(0,len(self),   str(key))
            self.set_value(1,len(self)-1, str(value))