code: def acq(self, graph):
          ''' estimate the value of generated graph
          '''
          mean, std = self.gpr.predict(np.array([graph.extract_descriptor()]))
          if self.optimizemode is OptimizeMode.Maximize:
              return mean + self.beta * std
          return mean - self.beta * stf acq(self, graph):
          ''' estimate the value of generated graph
          '''
          mean, std = self.gpr.predict(np.array([graph.extract_descriptor()]))
          if self.optimizemode is OptimizeMode.Maximize:
              return mean + self.beta * std
          return mean - self.beta * std
docs: estimate the value of generated graph