Top panels: genuine \pd correlation function as a function of $k^{*}$ obtained from Pb--Pb collisions at $\sqrt{s_{\rm NN}} = $ 5.02 TeV in the 0-10$\%$ (a), 10-30$\%$ (b) and 30--50$\%$ (c) centrality intervals, respectively. The measured data are shown as black open markers, while the vertical lines and the boxes represent the statistical and systematic uncertainties, respectively. The correlation functions are shown together with a fit band of 1$\sigma$ uncertainties performed using the three-body approach employing AV18+UIX potentials (Pisa fit, red bands) and using the Lednick\'y--Lyuboshitz approach (L--L fit, blue bands) The non-femtoscopic background contributions are represented by the light cyan band. Bottom panels: $n_{\sigma}$ calculated as data-to-fit difference, normalized by the total uncertainty of experimental data.