def plural_of(noun):
    """Returns the plural from of the (english) `noun`.

    >>> print (plural_of ("house"))
    houses
    >>> print (plural_of ("address"))
    addresses
    >>> print (plural_of ("enemy"))
    enemies

    """
    result = noun
    if result.endswith('s'):
        result += 'es'
    elif result.endswith('y'):
        result = result[:-1] + 'ies'
    else:
        result += 's'
    return result
