Given a hemisphere identifier, set the sign of the coordinate to match that hemisphere

def set_hemisphere(self, hemi_str):
        '''
        Given a hemisphere identifier, set the sign of the coordinate to match that hemisphere
        '''
        if hemi_str == 'W':
            self.degree = abs(self.degree)*-1
            self.minute = abs(self.minute)*-1
            self.second = abs(self.second)*-1
            self._update()
        elif hemi_str == 'E':
            self.degree = abs(self.degree)
            self.minute = abs(self.minute)
            self.second = abs(self.second)
            self._update()
        else:
            raise ValueError('Hemisphere identifier for longitudes must be E or W')