def class_option(argument):
 if (argument is None):
  raise ValueError('argument required but none supplied')
 names = argument.split()
 class_names = []
 for name in names:
  class_name = nodes.make_id(name)
  if (not class_name):
   raise ValueError(('cannot make "%s" into a class name' % name))
  class_names.append(class_name)
 return class_names

def class_option ( argument ) : if ( argument is None ) : raise ValueError ( 'argument required but none supplied' ) names = argument . split ( ) class_names = [ ] for name in names : class_name = nodes . make_id ( name ) if ( not class_name ) : raise ValueError ( ( 'cannot make "%s" into a class name' % name ) ) class_names . append ( class_name ) return class_names
convert the argument into a list of id-compatible strings and return it .