code: def changed(requestContext, seriesList):
      
      for series in seriesList:
          series.name = series.pathExpression = 'changed(%s)' % series.name
          previous = None
          for index, value in enumerate(series):
              if previous is None:
                  series[index] = 0
              elif value is not None and previous != value:
                  series[index] = 1
              else:
                  series[index] = 0
              previous = value
      return seriesList
docs: Takes one metric or a wildcard seriesList.
      Output 1 when the value changed, 0 when null or the same
      Example::
  
          &target=changed(Server01.connections.handled)