fn get_notes(env: soroban_sdk::Env) -> soroban_sdk::Vec
fn create_note(
env: soroban_sdk::Env,
title: soroban_sdk::String,
content: soroban_sdk::String,
) -> soroban_sdk::String
fn delete_note(env: soroban_sdk::Env, id: u64) -> soroban_sdk::String