code: public Boolean isSet(String option) {
          if (delegateMap.containsKey(option)) {
              Object entry = delegateMap.get(option);
              if (!(entry instanceof ConfigObject) || !((ConfigObject) entry).isEmpty()) {
                  return Boolean.TRUE;
              }
          }
          return Boolean.FALSE;
      }
docs: Checks if a config option is set. Example usage:
  <pre class="groovyTestCase">
  def config = new ConfigSlurper().parse("foo { password='' }")
  assert config.foo.isSet('password')
  assert config.foo.isSet('username') == false
  </pre>
  
  The check works <b>only</v> for options <b>one</b> block below the current block.
  E.g. <code>config.isSet('foo.password')</code> will always return false.
  
  @param option The name of the option
  @return <code>true</code> if the option is set <code>false</code> otherwise
  @since 2.3.0