new_contents: import components as comp
  from model import DnaModel
  
  #for plotting:
  from numpy import linspace
  import matplotlib.pyplot as plt
  
  def round_down(num, divisor):
      return num - (num%divisor)
  def round_up(num, divisor):
      return num + (num%divisor)
  
  #actual test:
  class DoublePinchHexTest(DnaModel):
      def run(self):
          heatex = self.addComponent(comp.PinchHex, 'heatex').nodes(1, 2, 3, 4)
  
          self.nodes[1].update({
              'media': 'other',
              'cp': 1.5617, #kJ/kg*K
              't': 430,
              'p': 0.857
          })
  
          self.nodes[3].update({
              'media': 'kalina',
              'y': 0.7,
              't': 85,
              'p': 100,
              'mdot': 1
          })
  
  
          heatex.calc(Nseg = 11, dTmin = 5)
  
          return self
  
      def plot(self):
          print('Plotting...')
  
          result = self.result['heatex']
          #plot
          x = linspace(0, 1, len(result['Th']))
          miny = round_down(min(min(result['Tc']), min(result['Th']))-1, 10)
          maxy = round_up(max(max(result['Tc']), max(result['Th']))+1, 10)
          plt.plot(x, result['Th'], 'r->', label = 'Hot')
          plt.plot(x, result['Tc'], 'b-<', label = 'Cold')
          plt.xlabel('Location in HEX')
          plt.ylabel(r'Temperature [$^\circ$C]')
          plt.title('Hot/cold flows through HEX - pinch: ' + str(round(result['dTmin'], 2)) + ' [K]')
          plt.ylim(miny, maxy)
          plt.grid(True)
          plt.savefig('../output/dblPinchHexTest.png')
          plt.close()
  
          return self
  
      def analyse(self):
          n = self.nodes
  
          print('Hot inlet: ',n[1])
          print('Hot outlet: ',n[2])
          print('Hot mdot:', n[1]['mdot'], '(expected ~5.8)')
          print('Energy difference: ', n[1]['mdot'] * (n[2]['h'] - n[1]['h']),' (expected -2245.094)')
  
          print('Cold inlet: ',n[3])
          print('Cold outlet: ',n[4])
          print('Cold mdot:', n[3]['mdot'], '(expected ~1)')
          print('Energy difference: ', n[3]['mdot'] * (n[4]['h'] - n[3]['h']),' (expected  2245.094)')
  
          return self
subject: Add a broken test for a Double Pinch Heat Exchanger