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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 keyPressEvent(self, event):
 """Reimplemented Qt Method to avoid removing the header."""

        event, text, key, ctrl, shift = restore_keyevent(event)
        cursor_position = self.get_position('cursor')

        if cursor_position < self.header_end_pos:
            self.restrict_cursor_position(self.header_end_pos, 'eof')
        elif key == Qt.Key_Delete:
            if self.has_selected_text():
                self.remove_text()
            else:
                self.stdkey_clear()
        elif key == Qt.Key_Backspace:
            if self.has_selected_text():
                self.remove_text()
            elif self.header_end_pos == cursor_position:
                return
            else:
                self.stdkey_backspace()
        elif key == Qt.Key_X and ctrl:
            self.cut()
        else:
            CodeEditor.keyPressEvent(self, event)