code: def isNonNull(requestContext, seriesList):
      
  
      def transform(v):
          if v is None:
              return 0
          else:
              return 1
  
      for series in seriesList:
          series.name = "isNonNull(%s)" % (series.name)
          series.pathExpression = series.name
          values = [transform(v) for v in series]
          series.extend(values)
          del series[:len(values)]
      return seriesList
docs: Takes a metric or wild card seriesList and counts up how many
      non-null values are specified. This is useful for understanding
      which metrics have data at a given point in time (ie, to count
      which servers are alive).
  
      Example::
  
          &target=isNonNull(webapp.pages.*.views)
  
      Returns a seriesList where 1 is specified for non-null values, and
      0 is specified for null values.