<li><strong>All <codeclass="python hljs"><spanclass="hljs-string">'cdef'</span></code> definitions are optional, but they contribute to the speed-up.</strong></li>
<li><strong>Script needs to be saved with a <codeclass="python hljs"><spanclass="hljs-string">'pyx'</span></code> extension.</strong></li>
<div><h3id="virtualenvironments">Virtual Environments</h3><p><strong>System for installing libraries directly into project's directory.</strong></p><pre><codeclass="bash language-bash hljs">$ python3 -m venv <name><spanclass="hljs-comment"># Creates virtual environment in current directory.</span>
$ <spanclass="hljs-built_in">source</span><name>/bin/activate <spanclass="hljs-comment"># Activates venv. On Windows run `<name>\Scripts\activate`.</span>