where a type element is a union of one or more <i>type terms</i>.
A type term is either a single type or a single underlying type.
</p>

<h4 id="Basic_interfaces">Basic interfaces</h4>

<p>
In its most basic form an interface specifies a (possibly empty) list of methods.
The type set defined by such an interface is the set of types which implement all of

* Fix typo in documentation for [Simple HTTP Basic Auth](https://fastapi.tiangolo.com/advanced/security/http-basic-auth/#simple-http-basic-auth). PR [#514](https://github.com/tiangolo/fastapi/pull/514) by [@prostomarkeloff](https://github.com/prostomarkeloff).