def validate_extra_file(val):
 try:
  (val % {'language': 'cs'})
 except Exception as error:
  raise ValidationError((_('Bad format string (%s)') % str(error)))

def validate_extra_file ( val ) : try : ( val % { 'language' : 'cs' } ) except Exception as error : raise ValidationError ( ( _ ( 'Bad format string (%s)' ) % str ( error ) ) )
validates extra file to commit .