def pluralize(singular):
    """Convert singular word to its plural form.

    Args:
        singular: A word in its singular form.

    Returns:
        The word in its plural form.
    """
    if singular in UNCOUNTABLES:
        return singular
    for i in IRREGULAR:
        if i[0] == singular:
            return i[1]
    for i in PLURALIZE_PATTERNS:
        if re.search(i[0], singular):
            return re.sub(i[0], i[1], singular)
Convert singular word to its plural form.

    Args:
        singular: A word in its singular form.

    Returns:
        The word in its plural form.