Sets the sub-title for this page to the inputed title.

        :param      title | <str>

def setSubTitle(self, title):
        """
        Sets the sub-title for this page to the inputed title.

        :param      title | <str>
        """
        self._subTitleLabel.setText(title)
        self._subTitleLabel.adjustSize()
        self.adjustMargins()