def METHOD_NAME(self, qp: QtGui.QPainter):
    if len(self.data11) == 0 and len(self.reference11) == 0:
        return
    pen = QtGui.QPen(Chart.color.sweep)
    pen.setWidth(self.dim.point)
    line_pen = QtGui.QPen(Chart.color.sweep)
    line_pen.setWidth(self.dim.line)
    highlighter = QtGui.QPen(QtGui.QColor(20, 0, 255))
    highlighter.setWidth(1)
    if not self.fixedSpan:
        if len(self.data11) > 0:
            fstart = self.data11[0].freq
            fstop = self.data11[len(self.data11) - 1].freq
        else:
            fstart = self.reference11[0].freq
            fstop = self.reference11[len(self.reference11) - 1].freq
        self.fstart = fstart
        self.fstop = fstop
    else:
        fstart = self.fstart = self.minFrequency
        fstop = self.fstop = self.maxFrequency
    # Draw bands if required
    if self.bands.enabled:
        self.drawBands(qp, fstart, fstop)
    self.calc_scaling()
    self.draw_grid(qp)
    if self.data11:
        c = QtGui.QColor(Chart.color.sweep)
        c.setAlpha(255)
        pen = QtGui.QPen(c)
        pen.setWidth(2)
        qp.setPen(pen)
        qp.drawLine(33, 9, 38, 9)
        c = QtGui.QColor(Chart.color.sweep_secondary)
        c.setAlpha(255)
        pen = QtGui.QPen(c)
        pen.setWidth(2)
        qp.setPen(pen)
        qp.drawLine(
            self.leftMargin + self.dim.width - 20,
            9,
            self.leftMargin + self.dim.width - 15,
            9,
        )
    if self.reference11:
        c = QtGui.QColor(Chart.color.reference)
        c.setAlpha(255)
        pen = QtGui.QPen(c)
        pen.setWidth(2)
        qp.setPen(pen)
        qp.drawLine(33, 14, 38, 14)
        c = QtGui.QColor(Chart.color.reference_secondary)
        c.setAlpha(255)
        pen = QtGui.QPen(c)
        pen.setWidth(2)
        qp.setPen(pen)
        qp.drawLine(
            self.leftMargin + self.dim.width - 20,
            14,
            self.leftMargin + self.dim.width - 15,
            14,
        )
    self.drawData(qp, self.data11, Chart.color.sweep)
    self.drawData(qp, self.data21, Chart.color.sweep_secondary)
    self.drawData(qp, self.reference11, Chart.color.reference)
    self.drawData(qp, self.reference21, Chart.color.reference_secondary)
    self.drawMarkers(qp, data=self.data11)
    self.drawMarkers(qp, data=self.data21)