#[derive(Debug)]
struct BlockReference {
    multi_hash: String,
}

impl BlockReference {
    fn from_str(s: &str) -> BlockReference {
        BlockReference { multi_hash: s.to_string() }
    }
}

fn main() {
    let block_reference: BlockReference = "QmWATWQ7fVPP2EFGu71UkfnqhYXDYH566qy47CnJDgvs8u".parse();
    println!("{:?}", block_reference);
}