code: def getSensorLimits(self):
          
          limits = []
          for i in range(len([b for b in self.env.case.buses if b.type == PQ])):
              limits.append((0.0, self.env._Pd0[i]))
  
          logger.info("Sensor limits: %s" % limits)
  
          return limits
docs: Returns a list of 2-tuples, e.g. [(-3.14, 3.14), (-0.001, 0.001)],
          one tuple per parameter, giving min and max for that parameter.