old_contents: from  .Resource import names_registered, resource_by_name
  
  def build():
      for name in names_registered():
          resource = resource_by_name(name)()
          for explanation in resource:
              r = explanation
              for functor in resource.modifiers:
                  r = functor(r)
              # write res in file 'name'
              print(r)
  
new_contents: from .Resource import names_registered, resource_by_name
  
  
  def build():
      for name in names_registered():
          resource = resource_by_name(name)()
          for explanation in resource:
              r = explanation
              for functor in resource.modifiers:
                  if r is None:
                      break
                  r = functor(r)
              if r is None:
                  continue
              # write res in file 'name'
              print(r)
  
subject: Add None check while applying modifiers