code: def potential(__func__=None, **kwds):
      
      def instantiate_pot(__func__):
          junk, parents = _extract(
              __func__, kwds, keys, 'Potential', probe=False)
          return Potential(parents=parents, **kwds)
  
      keys = ['logp']
  
      instantiate_pot.kwds = kwds
  
      if __func__:
          return instantiate_pot(__func__)
  
      return instantiate_pot
docs: Decorator function instantiating potentials. Usage:
  
      @potential
      def B(parent_name = ., ...)
          return baz(parent_name, ...)
  
      where baz returns the deterministic B's value conditional
      on its parents.
  
      :SeeAlso:
        Deterministic, deterministic, Stochastic, Potential, stochastic, data, Model