* Processing a response after being generated by *path operation functions* but before returning it. E.g. adding custom headers, logging, adding extra metadata.
    * New docs section: [Custom Request and APIRoute class](https://fastapi.tiangolo.com/advanced/custom-request-and-route/).

the associativity of the operators.  Explicit parentheses affect the evaluation
by overriding the default associativity.
In the expression <code>x + (y + z)</code> the addition <code>y + z</code>
is performed before adding <code>x</code>.
</p>

<h2 id="Statements">Statements</h2>

<p>
Statements control execution.
</p>

<pre class="ebnf">
Statement =
	Declaration | LabeledStmt | SimpleStmt |