that can be converted to type <code>T</code>.
</p>

<pre class="ebnf">
Conversion = Type "(" Expression [ "," ] ")" .
</pre>

<p>
If the type starts with the operator <code>*</code> or <code>&lt;-</code>,
or if the type starts with the keyword <code>func</code>
and has no result list, it must be parenthesized when
necessary to avoid ambiguity:
</p>

<pre>

legacy_request_state_context_var: ContextVar[Optional[Dict[str, Any]]] = ContextVar(
    "legacy_request_state_context_var", default=None
)

async def set_up_request_state_dependency():
    request_state = {"user": "deadpond"}
    contextvar_token = legacy_request_state_context_var.set(request_state)
    yield request_state
    legacy_request_state_context_var.reset(contextvar_token)
```