 <span class="hljs-title function_">assert</span>(<span class="hljs-title function_">isObject</span>(<span class="hljs-variable language_">this</span>), <span class="hljs-string">'this is not an object'</span>);
    <span class="hljs-title function_">assert</span>(<span class="hljs-variable language_">this</span> <span class="hljs-keyword">instanceof</span> <span class="hljs-title class_">Map</span>, <span class="hljs-string">'this is not a Map instance'</span>);
    <span class="hljs-keyword">for</span>(<s