```rust
use appwrite::Client;
use appwrite::services::Project;
#[tokio::main]
async fn main() -> Result<(), Box<dyn std::error::Error>> {
let client = Client::new();
client.set_endpoint("https://<REGION>.cloud.appwrite.io/v1"); // Your API Endpoint
client.set_project("<YOUR_PROJECT_ID>"); // Your project ID
client.set_key("<YOUR_API_KEY>"); // Your secret API key
let project = Project::new(&client);
let result = project.update_email_template(
appwrite::enums::EmailTemplateType::Verification,
Some(appwrite::enums::EmailTemplateLocale::Af), // optional
Some("<SUBJECT>"), // optional
Some("<MESSAGE>"), // optional
Some("<SENDER_NAME>"), // optional
Some("email@example.com"), // optional
Some("email@example.com"), // optional
Some("<REPLY_TO_NAME>") // optional
).await?;
let _ = result;
Ok(())
}
```