chore: checkpoint before Python removal

vendor/valuable/examples/derive.rs

@@ -0,0 +1,26 @@
+use valuable::Valuable;
+
+use std::collections::HashMap;
+
+// `Debug` not implemented for struct, the debug implementation is going via
+// valuable.
+#[derive(Valuable)]
+struct Person {
+    name: String,
+    age: u8,
+    phones: Vec<String>,
+    favorites: HashMap<String, String>,
+}
+
+fn main() {
+    let mut p = Person {
+        name: "John Doe".to_string(),
+        age: 42,
+        phones: vec!["876-5309".to_string()],
+        favorites: HashMap::new(),
+    };
+
+    p.favorites.insert("color".to_string(), "blue".to_string());
+
+    println!("{:#?}", p.as_value());
+}