> decorator that takes a default value now
            passes that value by name rather than eagerly evaluating it.</p>
    </li>
    <li>
        <p><code>Environments</code>: The <code>defineIfNew</code> method now takes both of its Environment arguments by
            name.</p>
    </li>
    <li>
        <p><code>Tree</code>: The <code>CheckTree</code> version of <code>Tree</code> construction now includes more
            information in the exception reason if the structure is not a tree. Instead of jus