How to use the pyxrf.core.fitting.rfactor_compute function in pyxrf

if plot_single_point and (self.incident_energy_shift_keV ==
                                          self.incident_energy_shift_keV_updated):
                    # fit_real_time = False
                    fit_real_time = True  # For now let's always do fitting on the fly
                if fit_real_time:
                    # Interpolate references (same function as in the main processing routine)
                    refs = _interpolate_references(self.energy, self.ref_energy, self.ref_data)
                    xanes_fit_pt, xanes_fit_rfactor, _ = fit_spectrum(data_selected,
                                                                      refs,
                                                                      method=self.fitting_method,
                                                                      rate=self.fitting_descent_rate)
                else:
                    # Use precomputed data
                    xanes_fit_pt = self.xanes_map_data[:, yd_px_min, xd_px_min]
                    # We still compute R-factor
                    xanes_fit_rfactor = rfactor_compute(data_selected, xanes_fit_pt, self.absorption_refs)

                # Compute fit results represented in counts (for output)
                xanes_fit_pt_counts = xanes_fit_pt.copy()
                for n, v in enumerate(xanes_fit_pt):
                    xanes_fit_pt_counts[n] = v * np.sum(self.absorption_refs[:, n])

                for n, v in enumerate(xanes_fit_pt_counts):
                    plot_comments += f"\n{self.ref_labels[n]}: {xanes_fit_pt_counts[n]:.2f} c."
                plot_comments += f"\nR-factor: {xanes_fit_rfactor:.5g}"

                # Labels should always be supplied when calling the function.
                #   This is not user controlled option, therefore exception should be raised.
                assert self.labels, "No labels are provided. Fitting results can not be displayed properly"

                refs_scaled = self.absorption_refs.copy()
                _, n_refs = refs_scaled.shape