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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def pgrrec(body, lon, lat, alt, re, f):
 """ Convert planetographic coordinates to rectangular coordinates. http://naif.jpl.nasa.gov/pub/naif/toolkit_docs/C/cspice/pgrrec_c.html :param body: Body with which coordinate system is associated. :type body: str :param lon: Planetographic longitude of a point (radians). :type lon: float :param lat: Planetographic latitude of a point (radians). :type lat: float :param alt: Altitude of a point above reference spheroid. :type alt: float :param re: Equatorial radius of the reference spheroid. :type re: float :param f: Flattening coefficient. :type f: float :return: Rectangular coordinates of the point. :rtype: 3-Element Array of floats """

    body = stypes.stringToCharP(body)
    lon = ctypes.c_double(lon)
    lat = ctypes.c_double(lat)
    alt = ctypes.c_double(alt)
    re = ctypes.c_double(re)
    f = ctypes.c_double(f)
    rectan = stypes.emptyDoubleVector(3)
    libspice.pgrrec_c(body, lon, lat, alt, re, f, rectan)
    return stypes.cVectorToPython(rectan)