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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 text_changed(self):

 """Text has changed"""

        # Save text as bytes, if it was initially bytes
        if self.is_binary:
            self.text = to_binary_string(self.edit.toPlainText(), 'utf8')
        else:
            self.text = to_text_string(self.edit.toPlainText())
        if self.btn_save_and_close:
            self.btn_save_and_close.setEnabled(True)
            self.btn_save_and_close.setAutoDefault(True)
            self.btn_save_and_close.setDefault(True)