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

def eigenvalues(self):
        import slepc4py
        slepc4py.init()
        from slepc4py import SLEPc
        E = SLEPc.EPS(); E.create()

        E.setOperators(self.A)
        E.setProblemType(SLEPc.EPS.ProblemType.NHEP)
        E.setDimensions(1)
        E.setWhichEigenpairs(SLEPc.EPS.Which.SMALLEST_REAL)
        E.setFromOptions()
        E.solve()
        n = E.getConverged()
        for i in range(0, n):
            print(E.getEigenvalue(0))
        return

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)
                        if "spectral_shift" in parameters:
                            self.eps.setTarget(parameters["spectral_shift"])
                    elif value == "target imaginary":
                        self.eps.setWhichEigenpairs(SLEPc.EPS.Which.TARGET_IMAGINARY)
                        if "spectral_shift" in parameters:
                            self.eps.setTarget(parameters["spectral_shift"])