title: Why this error? "No such property: Entry for class: java.util.Map"
body: <p>I'm following an example from <a href="https://issues.jenkins-ci.org/browse/JENKINS-44085?focusedCommentId=346951&amp;page=com.atlassian.jira.plugin.system.issuetabpanels%3Acomment-tabpanel#comment-346951" rel="nofollow noreferrer">JENKINS-44085</a> issue very-bottom comments about creating a stage map almost to the T, but when I execute my code I get</p>
  
  <pre><code>No such property: Entry for class: java.util.Map
  </code></pre>
  
  <p>Here's my code. Variable 'pipeline' is defined somewhere else, and is valid.</p>
  
  <pre><code>def generateStage(String job, String targetVersion,
                    String rootVersion, Integer sleepTime=0) {
      return {
          stage("Deploying: ${job}") {
                sleep sleepTime
                pipeline.executeDeploymentPipeline(job,
                                                   targetVersion,
                                                   rootVersion)
          }
      }
  }
  
  def deployProcs(targetVersion, rootVersion) {
      int sleepTime = 0
      def procs = ["proc-proc", "proc-proc-high"]
      def parallelStagesMap = procs.collectEntries {
          ["${it}" : generateStage(it, targetVersion, rootVersion, sleepTime)]
          sleepTime += 5
      }
      parallel parallelStagesMap
  }
  </code></pre>
  
  <p>Why is that?</p>