code: def _check_versionlock():
      '''
      Ensure that the appropriate versionlock plugin is present
      '''
      if _yum() == 'dnf':
          if int(__grains__.get('osmajorrelease')) >= 26:
              if six.PY3:
                  vl_plugin = 'python3-dnf-plugin-versionlock'
              else:
                  vl_plugin = 'python2-dnf-plugin-versionlock'
          else:
              if six.PY3:
                  vl_plugin = 'python3-dnf-plugins-extras-versionlock'
              else:
                  vl_plugin = 'python-dnf-plugins-extras-versionlock'
      else:
          vl_plugin = 'yum-versionlock' \
              if __grains__.get('osmajorrelease') == '5' \
              else 'yum-plugin-versionlock'
  
      if vl_plugin not in list_pkgs():
          raise SaltInvocationError(
              'Cannot proceed, {0} is not installed.'.format(vl_plugin)
          f _check_versionlock():
      '''
      Ensure that the appropriate versionlock plugin is present
      '''
      if _yum() == 'dnf':
          if int(__grains__.get('osmajorrelease')) >= 26:
              if six.PY3:
                  vl_plugin = 'python3-dnf-plugin-versionlock'
              else:
                  vl_plugin = 'python2-dnf-plugin-versionlock'
          else:
              if six.PY3:
                  vl_plugin = 'python3-dnf-plugins-extras-versionlock'
              else:
                  vl_plugin = 'python-dnf-plugins-extras-versionlock'
      else:
          vl_plugin = 'yum-versionlock' \
              if __grains__.get('osmajorrelease') == '5' \
              else 'yum-plugin-versionlock'
  
      if vl_plugin not in list_pkgs():
          raise SaltInvocationError(
              'Cannot proceed, {0} is not installed.'.format(vl_plugin)
          )
docs: Ensure that the appropriate versionlock plugin is present