text: from PhotochemPy import PhotochemPy
  
  template = 'Archean2Proterozoic'
  sun = 'Sun_2.7Ga.txt'
  
  pc = PhotochemPy('../input/templates/'+template+'/species.dat', \
                   '../input/templates/'+template+'/reactions.rx', \
                   '../input/templates/'+template+'/settings.yaml', \
                   '../input/templates/'+template+'/atmosphere.txt', \
                   '../input/templates/'+template+'/'+sun)
  
  converged = pc.integrate(method='Backward_Euler')
  converged = pc.integrate(method='CVODE_BDF')
  