def test_withHeading(self):
        """
        Variation values get combined with headings correctly.
        """
        trueHeading, variation, direction = "123.12", "1.34", "E"
        sentenceData = {'trueHeading': trueHeading,
                        'magneticVariation': variation,
                        'magneticVariationDirection': direction}
        heading = base.Heading.fromFloats(float(trueHeading),
                                          variationValue=float(variation))
        self._fixerTest(sentenceData, {'heading': heading})

        Variation values get combined with headings correctly.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/positioning/test/test_nmea.py