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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 paintEvent(self, event):
 """Fills the panel background using QPalette."""

        if self.isVisible() and self.position != self.Position.FLOATING:
            # fill background
            self._background_brush = QBrush(QColor(
                self.editor.sideareas_color))
            self._foreground_pen = QPen(QColor(
                self.palette().windowText().color()))
            painter = QPainter(self)
            painter.fillRect(event.rect(), self._background_brush)