title: Is it possible to do string substitution in YAML?
body: <p>Is there a way to substitute string in YAML. For example, I would like to define <code>sub</code> once and use it throughout the YAML file. </p>
  
  <pre><code>sub: ['a', 'b', 'c']
  command:
      params:
          cmd1:
              type: string
              enum :   # Get the list defined in 'sub'
              description: Exclude commands from the test list.
          cmd2:
              type: string
              enum:   # Get the list defined in 'sub'
  </code></pre>