Up to now, for several options, the only way to apply them to a group of *path operations* was in `include_router`. That works well, but the call to `app.include_router()` or `router.include_router()` is normally done in another file.

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The array underlying a slice may extend past the end of the slice.
The <i>capacity</i> is a measure of that extent: it is the sum of
the length of the slice and the length of the array beyond the slice;
a slice of length up to that capacity can be created by
<a href="#Slice_expressions"><i>slicing</i></a> a new one from the original slice.
The capacity of a slice <code>a</code> can be discovered using the