title: No such DSL method 'publishHTML' found among steps
body: <p>I have a jenkins DSL step that runs my python nosetests and creates a unittest coverage report.</p>
  
  <p>Here is my jenkins stage.</p>
  
  <pre><code>stage ('Unit Tests') {
              steps {
                  sh """
                      #. venv/bin/activate
                      export PATH=${VIRTUAL_ENV}/bin:${PATH}
                      make unittest || true
                  """
              }
  
              post {
                  always {
                      junit keepLongStdio: true, testResults: 'report/nosetests.xml'
                      publishHTML target: [
                          reportDir: 'report/coverage',
                          reportFiles: 'index.html',
                          reportName: 'Coverage Report - Unit Test'
                      ]
                  }
              }
          }
  </code></pre>
  
  <p>I get this error - </p>
  
  <p>java.lang.NoSuchMethodError: No such DSL method 'publishHTML' found among steps.</p>
  
  <p>How can I fix this error? I got this piece of code from a different repository.</p>