code: def calculable(self):
          
          self._mode = ""
          if self.kwargs["T"] and self.kwargs["P"]:
              self._mode = "TP"
          elif self.kwargs["T"] and self.kwargs["rho"]:
              self._mode = "Trho"
          elif self.kwargs["P"] and self.kwargs["rho"]:
              self._mode = "Prho"
  
          # Composition definition
          self._composition = ""
          if self.kwargs["A"] is not None:
              self._composition = "A"
          elif self.kwargs["xa"] is not None:
              self._composition = "xa"
  
          return bool(self._mode) and bool(self._composition)
docs: Check if inputs are enough to define state