code: def _bubbleP(cls, T):
          
          c = cls._blend["bubble"]
          Tj = cls._blend["Tj"]
          Pj = cls._blend["Pj"]
          Tita = 1-T/Tj
  
          suma = 0
          for i, n in zip(c["i"], c["n"]):
              suma += n*Tita**(i/2.)
          P = Pj*exp(Tj/T*suma)
          return P
docs: Using ancillary equation return the pressure of bubble point