How to use the slepc4py.SLEPc.EPS.Which.LARGEST_MAGNITUDE function in slepc4py

elif value == "jacobi-davidson":
                        self.eps.setType(SLEPc.EPS.Type.JD)
                    elif value == "generalized-davidson":
                        self.eps.setType(SLEPc.EPS.Type.GD)
                    else:
                        raise RuntimeError("Invalid solver type")
                elif key == "spectral_shift":
                    st = self.eps.getST()
                    st.setShift(value)
                elif key == "spectral_transform":
                    assert value == "shift-and-invert"
                    st = self.eps.getST()
                    st.setType(SLEPc.ST.Type.SINVERT)
                elif key == "spectrum":
                    if value == "largest magnitude":
                        self.eps.setWhichEigenpairs(SLEPc.EPS.Which.LARGEST_MAGNITUDE)
                    elif value == "smallest magnitude":
                        self.eps.setWhichEigenpairs(SLEPc.EPS.Which.SMALLEST_MAGNITUDE)
                    elif value == "largest real":
                        self.eps.setWhichEigenpairs(SLEPc.EPS.Which.LARGEST_REAL)
                    elif value == "smallest real":
                        self.eps.setWhichEigenpairs(SLEPc.EPS.Which.SMALLEST_REAL)
                    elif value == "largest imaginary":
                        self.eps.setWhichEigenpairs(SLEPc.EPS.Which.LARGEST_IMAGINARY)
                    elif value == "smallest imaginary":
                        self.eps.setWhichEigenpairs(SLEPc.EPS.Which.SMALLEST_IMAGINARY)
                    elif value == "target magnitude":
                        self.eps.setWhichEigenpairs(SLEPc.EPS.Which.TARGET_MAGNITUDE)
                        if "spectral_shift" in parameters:
                            self.eps.setTarget(parameters["spectral_shift"])
                    elif value == "target real":
                        self.eps.setWhichEigenpairs(SLEPc.EPS.Which.TARGET_REAL)