//! How to require presence of at least N values,
//! like `val1 val2 ... valN ... valM`.
//!
//! Running this example with --help prints this message:
//! -----------------------------------------------------
//! structopt 0.3.25
//!
//! USAGE:
//! at_least_two <foos>...
//!
//! FLAGS:
//! -h, --help Prints help information
//! -V, --version Prints version information
//!
//! ARGS:
//! <foos>...
//! -----------------------------------------------------
use StructOpt;