fit is performed simultaneously in all final states and in all bins of the observable considered in the measurement, assuming a Higgs boson mass of $m_{\PH} = 125.0\GeV$. The integrated cross section measurement is treated as a special case with a single bin. This implementation of the procedure for the unfolding of the detector effects from the observed distributions is different from the implementations commonly used in the experimental measurements, such as those discussed in Ref. [@Prosper:2011zz], where signal extraction and unfolding are performed in two separate steps. It is similar to the approach adopted in Ref. [@CMS:HIG-14-016].

The shape of the resonant signal contribution, $\mathcal{P}_{\text{res}}(m_{4\ell})$, is described by a double-sided Crystal Ball function as detailed in Ref. [@Chatrchyan:2013mxa], with a normalization proportional to the fiducial cross section $\sigma_{\mathrm{fid}}$. The shape of the combinatorial signal contribution, $\mathcal{P}_{\text{comb}}(m_{4\ell})$, from events where at least one of the four leptons does not originate from the ${\ensuremath{\PH \to 4\ell}\xspace}$ decay, is empirically modelled by a Landau distribution whose shape parameters are constrained in the fit to be within a range determined from simulation. The remaining freedom in these parameters results in an additional systematic uncertainty on the measured cross sections. This contribution is treated 