fn lookup_patch(&self, key: &NodeKey) -> Result<Option<Node>, DeserializeError> {
        let Some(patch) = &self.patch else {
            return Ok(None);
        };

        Ok(if patch.is_new_version(key.version) {
            patch.try_nodes(slice::from_ref(key))?.into_iter().next()
        } else {
            None
        })
    }
Returns `Ok(None)` if the patch is not responsible for the requested version.
core/lib/zk_os_merkle_tree/src/storage/mod.rs