code: def calculable(self):
          
          self._thermo = ""
          if self.kwargs["T"] and self.kwargs["P"]:
              self._thermo = "TP"
          elif self.kwargs["P"] and self.kwargs["h"] is not None:
              self._thermo = "Ph"
          elif self.kwargs["P"] and self.kwargs["s"] is not None:
              self._thermo = "Ps"
          # TODO: Add other pairs definitions options
          # elif self.kwargs["P"] and self.kwargs["v"]:
              # self._thermo = "Pv"
          # elif self.kwargs["T"] and self.kwargs["s"] is not None:
              # self._thermo = "Ts"
          elif self.kwargs["h"] is not None and self.kwargs["s"] is not None:
              self._thermo = "hs"
          elif self.kwargs["T"] and self.kwargs["x"] is not None:
              self._thermo = "Tx"
          elif self.kwargs["P"] and self.kwargs["x"] is not None:
              self._thermo = "Px"
          return self._thermo
docs: Check if class is calculable by its kwargs