chore: use_clap & clippy

src/sign.rs

@@ -1,5 +1,4 @@
 use clap::{ArgMatches, SubCommand, App, Arg};
-use crate::cmd::{Command, CommandError};
 use authenticator::{KeyHandle, AuthenticatorTransports, SignFlags};
 use std::sync::mpsc::channel;
 use authenticator::statecallback::StateCallback;
@@ -7,6 +6,7 @@ use authenticator::authenticatorservice::AuthenticatorService;
 use crate::fido;
 use crate::digest;
 use crate::fido::U2fV2Challenge;
+use rust_util::util_clap::{Command, CommandError};
 
 pub struct CommandImpl;
 
@@ -83,6 +83,6 @@ impl Command for CommandImpl {
 
         // u2f::authorization::parse_sign_response(app_id.to_string(), u2fv2_challenge_str.as_bytes().to_vec(), )
 
-        Ok(())
+        Ok(None)
     }
 }