* **Iterators returned by the [iter()](#iterator) function, such as list\_iterator and set\_iterator.**

* **Objects returned by the [itertools](#itertools) module, such as count, repeat and cycle.**

* **Generators returned by the [generator functions](#generator) and [generator expressions](#comprehension).**

* **All functions and classes have a call() method, hence are callable.**

<li><strong>Iterators returned by the <a href="#iterator">iter()</a> function, such as list_iterator and set_iterator.</strong></li>

<li><strong>Objects returned by the <a href="#itertools">itertools</a> module, such as count, repeat and cycle.</strong></li>

<li><strong>Generators returned by the <a href="#generator">generator functions</a> and <a href="#comprehension">generator expressions</a>.</strong></li>

</ul><div><h3 id="callable">Callable</h3><ul>

<li><strong>All functions and classes have a call() method, hence are callable.</strong></li>

<li><strong>When this cheatsheet uses <code class="python hljs"><span class="hljs-string">'&lt;function&gt;'</span></code> for an argument, it actually means <code class="python hljs"><span class="hljs-string">'&lt;callable&gt;'</span></code>.</strong></li>