'Print the keys in each item, one on each line'

def print_fields_std(self, items, keys, title=None):

    if (not items):
        return
    if title:
        print title
    for item in items:
        for key in keys:
            print ('%s:    %s' % (KEYS_TO_NAMES_EN[key], self.__conv_value(key, _get_item_key(item, key))))
