def _lenient_lowercase(lst):
 lowered = []
 for value in lst:
  try:
   lowered.append(value.lower())
  except AttributeError:
   lowered.append(value)
 return lowered

def _lenient_lowercase ( lst ) : lowered = [ ] for value in lst : try : lowered . append ( value . lower ( ) ) except AttributeError : lowered . append ( value ) return lowered
lowercase elements of a list .