chore: use_clap & clippy

src/register.rs

@@ -1,5 +1,4 @@
 use clap::{ArgMatches, SubCommand, App, Arg};
-use crate::cmd::{Command, CommandError};
 use authenticator::authenticatorservice::AuthenticatorService;
 use authenticator::statecallback::StateCallback;
 use authenticator::RegisterFlags;
@@ -7,6 +6,7 @@ use std::sync::mpsc::channel;
 use crate::fido;
 use crate::digest;
 use crate::fido::{U2fV2Challenge, U2fRegistrationData};
+use rust_util::util_clap::{Command, CommandError};
 
 pub struct CommandImpl;
 
@@ -85,7 +85,7 @@ impl Command for CommandImpl {
                 return simple_error!("Parse registration data failed: {}", e);
             }
         }
-        Ok(())
+        Ok(None)
     }
 }
 //