def _length_hint(obj):
 try:
  return len(obj)
 except (AttributeError, TypeError):
  try:
   get_hint = type(obj).__length_hint__
  except AttributeError:
   return None
  try:
   hint = get_hint(obj)
  except TypeError:
   return None
  if ((hint is NotImplemented) or (not isinstance(hint, int_types)) or (hint < 0)):
   return None
  return hint

def _length_hint ( obj ) : try : return len ( obj ) except ( AttributeError , TypeError ) : try : get_hint = type ( obj ) . __length_hint__ except AttributeError : return None try : hint = get_hint ( obj ) except TypeError : return None if ( ( hint is NotImplemented ) or ( not isinstance ( hint , int_types ) ) or ( hint < 0 ) ) : return None return hint
returns the length hint of an object .