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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 _mkAddBtnVisible(self):
 """ Ensure that the Add button is visible also when there are no tabs """

        if not self._btn_add_height:
#             self._btn_add_height = self.cornerWidget().height()
            self._btn_add_height = self._cwBtn.height()
        if self.count() == 0:
            
#             self.cornerWidget().setMinimumHeight(self._btn_add_height - 8)
            self._cwBtn.setMinimumHeight(self._btn_add_height - 8)
            self.setMinimumHeight(self._btn_add_height)