def pluralize(x: str) ->str:
    """Rudimentary pluralization function. It's used to name lists of things."""
    if x[-2:] in ['sh', 'ch', 'ss']:
        return x + 'es'
    elif x[-1:] in ['s', 'x', 'z']:
        return x + 'es'
    else:
        return x + 's'
