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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 disable_radio_button(self):
 """Disable radio button group and custom value input area."""

        checked = self.default_input_button_group.checkedButton()
        if checked:
            self.default_input_button_group.setExclusive(False)
            checked.setChecked(False)
            self.default_input_button_group.setExclusive(True)
        for button in self.default_input_button_group.buttons():
            button.setDisabled(True)
        self.custom_value.setDisabled(True)