old_contents: from .core import *
  from .builtin import *
  from .cpotential import CPotential
  from .cbuiltin import *
  
  from .lm10 import LM10Potential
  from .apw import PW14Potential
  from .pal5 import GC2Pal5Potential
  
new_contents: from .core import *
  from .builtin import *
  from .cpotential import CPotential
  from .cbuiltin import *
  
  from .lm10 import LM10Potential
  from .apw import PW14Potential
  
subject: remove pal5