Our version of the Physiological Equivalent Temperature (PET) comfort index, published in 2018 in Building&Environment has made it to pythermalcomforta project from the Center for the Built Environment (CBE) at UC Berkeley (amongst others S. Tartarini & S. Schiavon)
pyThermalComfort includes many other comfort metrics (PMV/PPD, SET, DR... a bit lost? A recap here) and the steady state PET is naturally added for a wider diffusion of this reference model.
More information in the documentation !