def METHOD_NAME(self):
    """ 
    Returns radiotools.coordinatesystem.cstrafo for shower geometry.
    Can be used to transform the radio pulses or the observer coordiates
    in the shower frame. Requieres the shower arrival direction 
    (azimuth and zenith angle) and magnetic field vector (parameters.showerParameters).
    Returns
    -------
    radiotools.coordinatesystem.cstrafo
    """
    if not self.has_parameter(parameters.showerParameters.azimuth) or \
       not self.has_parameter(parameters.showerParameters.zenith) or \
       not self.has_parameter(parameters.showerParameters.magnetic_field_vector):
        logger.error(
            "Magnetic field vector, azimuth or zenith angle not set! Can not return shower coordinatesystem.")
        raise ValueError(
            "Magnetic field vector, azimuth or zenith angle not set! Can not return shower coordinatesystem.")
    return coordinatesystems.cstrafo(self.get_parameter(parameters.showerParameters.zenith),
                                     self.get_parameter(parameters.showerParameters.azimuth),
                                     self.get_parameter(parameters.showerParameters.magnetic_field_vector))