Function resolve_invocation 

pub fn resolve_invocation<'s>(
    surface: &'s Surface,
    name: &str,
    matches: &ArgMatches,
) -> Result<(&'s Method, Call<'s>)>

Resolve a matched cassette invocation back into the method it names and the call to make.

matches is the cassette-level match; its own subcommand names the method. Executing the returned Call — and everything about where to send it — is the consumer’s.