code: def Region2_cp0(Tr, Pr):
      
      Jo = [0, 1, -5, -4, -3, -2, -1, 2, 3]
      no = [-0.96927686500217E+01, 0.10086655968018E+02, -0.56087911283020E-02,
            0.71452738081455E-01, -0.40710498223928E+00, 0.14240819171444E+01,
            -0.43839511319450E+01, -0.28408632460772E+00, 0.21268463753307E-01]
      go = log(Pr)
      gop = Pr**-1
      gopp = -Pr**-2
      got = gott = gopt = 0
      for j, ni in zip(Jo, no):
          go += ni * Tr**j
          got += ni*j * Tr**(j-1)
          gott += ni*j*(j-1) * Tr**(j-2)
      return go, gop, gopp, got, gott, gopt
docs: Ideal properties for Region 2
  
      Parameters
      ----------
      Tr : float
          Reduced temperature, [-]
      Pr : float
          Reduced pressure, [-]
  
      Returns
      -------
      prop : array
          Array with ideal Gibbs energy partial derivatives:
  
              * g: Ideal Specific Gibbs energy [kJ/kg]
              * gp: ∂g/∂P|T
              * gpp: ∂²g/∂P²|T
              * gt: ∂g/∂T|P
              * gtt: ∂²g/∂T²|P
              * gpt: ∂²g/∂T∂P
  
      References
      ----------
      IAPWS, Revised Release on the IAPWS Industrial Formulation 1997 for the
      Thermodynamic Properties of Water and Steam August 2007,
      http://www.iapws.org/relguide/IF97-Rev.html, Eq 16