How to use the pygeodesy.basics.property_RO function in PyGeodesy

    @property_RO
    def e12(self):
        '''Get M{1 - e**2} (C{float}).
        '''
        if self._e12 is None:
            self._e12 = 1 - self.e2
        return self._e12  # 1 - e2

    @property_RO
    def philam(self):
        '''Get the lat- and longitude (L{PhiLam2Tuple}C{(phi, lam)}).
        '''
        if self._philam is None:
            self._philam = PhiLam2Tuple(radians(self.lat),
                                        radians(self.lon))
        return self._xnamed(self._philam)

    @property_RO
    def zone(self):
        '''Get the polar pseudo zone (C{0}), like Karney's U{zone UPS}.
        '''
        return _UPS_ZONE

    @property_RO
    def phi(self):
        '''Get the latitude (B{C{radians}}).
        '''
        return self.philam.phi if self._philam is None else self._philam.phi

    @property_RO
    def height(self):
        '''Get this georef's height in C{meter} or C{None} if missing.
        '''
        if self._height is _Missing:
            self._decode()
        return self._height

    @property_RO
    def isNumpy2(self):
        '''Is this a Numpy2 wrapper?
        '''
        return True  # isinstance(self, (Numpy2LatLon, ...))

    @property_RO
    def _geodesic_Math2(self):
        '''(INTERNAL) Get this ellipsoid's C{Geodesic} and Karney's
           C{Math} class.
        '''
        if Ellipsoid._Math is None:
            from pygeodesy.karney import _wrapped
            Ellipsoid._Math = _wrapped.Math
        return self.geodesic, Ellipsoid._Math

    @property_RO
    def radius(self):
        '''Get the earth radius (C{meter}).
        '''
        return self._radius

    @property_RO
    def geodesic(self):
        '''Get this projection's I{wrapped} U{Karney Geodesic
           },
           provided package U{geographiclib
           } is installed.
        '''
        return self.datum.ellipsoid.geodesic

    @property_RO
    def equatoradius(self):
        '''Get the geodesic's equatorial (major) radius, semi-axis (C{meter}).
        '''
        return self.datum.ellipsoid.a