def _fixHemisphereSign(self, coordinateType, sentenceDataKey=None):
        """
        Fixes the sign for a hemisphere.

        This method must be called after the magnitude for the thing it
        determines the sign of has been set. This is done by the following
        functions:

            - C{self.FIXERS['magneticVariation']}
            - C{self.FIXERS['latitudeFloat']}
            - C{self.FIXERS['longitudeFloat']}

        @param coordinateType: Coordinate type. One of L{Angles.LATITUDE},
            L{Angles.LONGITUDE} or L{Angles.VARIATION}.
        @param sentenceDataKey: The key name of the hemisphere sign being
            fixed in the sentence data. If unspecified, C{coordinateType} is
            used.
        @type sentenceDataKey: C{str} (unless L{None})
        """
        sentenceDataKey = sentenceDataKey or coordinateType
        sign = self._getHemisphereSign(coordinateType)
        self._sentenceData[sentenceDataKey].setSign(sign)

        Fixes the sign for a hemisphere.

        This method must be called after the magnitude for the thing it
        determines the sign of has been set. This is done by the following
        functions:

            - C{self.FIXERS['magneticVariation']}
            - C{self.FIXERS['latitudeFloat']}
            - C{self.FIXERS['longitudeFloat']}

        @param coordinateType: Coordinate type. One of L{Angles.LATITUDE},
            L{Angles.LONGITUDE} or L{Angles.VARIATION}.
        @param sentenceDataKey: The key name of the hemisphere sign being
            fixed in the sentence data. If unspecified, C{coordinateType} is
            used.
        @type sentenceDataKey: C{str} (unless L{None})
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/positioning/nmea.py