code: def API(self):
          r'''API gravity of the hypothetical liquid phase of the mixture, 
          [degrees]. The reference condition is water at 15.6 °C (60 °F) and 1 atm 
          (rho=999.016 kg/m^3, standardized).
              
          Examples
          --------
          >>> Mixture(['hexane', 'decane'], ws=[0.5, 0.5]).API
          71.34707841728181
          '''
          Vml = self.VolumeLiquidMixture(T=288.70555555555552, P=101325, zs=self.zs, ws=self.ws)
          if Vml:
              rho = Vm_to_rho(Vml, self.MW)
          sg = SG(rho, rho_ref=999.016)
          return SG_to_API(sgf API(self):
          r'''API gravity of the hypothetical liquid phase of the mixture, 
          [degrees]. The reference condition is water at 15.6 °C (60 °F) and 1 atm 
          (rho=999.016 kg/m^3, standardized).
              
          Examples
          --------
          >>> Mixture(['hexane', 'decane'], ws=[0.5, 0.5]).API
          71.34707841728181
          '''
          Vml = self.VolumeLiquidMixture(T=288.70555555555552, P=101325, zs=self.zs, ws=self.ws)
          if Vml:
              rho = Vm_to_rho(Vml, self.MW)
          sg = SG(rho, rho_ref=999.016)
          return SG_to_API(sg)
docs: r'''API gravity of the hypothetical liquid phase of the mixture, 
          [degrees]. The reference condition is water at 15.6 °C (60 °F) and 1 atm 
          (rho=999.016 kg/m^3, standardized).
              
          Examples
          --------
          >>> Mixture(['hexane', 'decane'], ws=[0.5, 0.5]).API
          71.34707841728181