code: def _water(cls, T, P):
          
          water = IAPWS95(P=P, T=T)
          prop = {}
          prop["g"] = water.h-T*water.s
          prop["gt"] = -water.s
          prop["gp"] = 1./water.rho
          prop["gtt"] = -water.cp/T
          prop["gtp"] = water.betas*water.cp/T
          prop["gpp"] = -1e6/(water.rho*water.w)**2-water.betas**2*1e3*water.cp/T
          prop["gs"] = 0
          prop["gsp"] = 0
          prop["thcond"] = water.k
          return prop
docs: Get properties of pure water, Table4 pag 8