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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 change_format(self):

 """Change display format"""

        format, valid = QInputDialog.getText(self, _( 'Format'),
                                 _( "Float formatting"),
                                 QLineEdit.Normal, self.model.get_format())
        if valid:
            format = str(format)
            try:
                format % 1.1
            except:
                QMessageBox.critical(self, _("Error"),
                                     _("Format (%s) is incorrect") % format)
                return
            self.model.set_format(format)