ing Java command line
 applications with almost zero code.

 <code>CommandLine</code> is in a single file, so it can be included in source form.
 This lets users run picocli-based applications without requiring picocli as an external dependency.
 </p>
 <h2>Classes and Interfaces for Defining a CommandSpec Model</h2>
 <p>
 <img src="doc-files/class-diagram-definition.png" alt="Classes and Interfaces for Defining a CommandSpec Model">
 </p>
 <h2>Classes Related to Parsing Command Line Arguments</h2>
 <p>
 <im