/**
* Section 1
**/
options = pipeline.PipelineOptions(self.__pipilineargs).view_as(BeamMainOptions)
with (beam.Pipeline(options=options)) as p:
   ...
/**
* Section 2
**/
   alines = p | 'Read a records' >> beam.io.ReadFromText(options.aFile)
...
/**
* Section 3
**/
   aMatrices = alines | 'String to A matrices' >> beam.ParDo(StringToMatrixFn())
...
/**
* Section 4
**/
   cogroupyresult = ({'firstmatrix':aMatrices, 'secondmatrix':dMatrices} |
      'Group for addition' >> beam.CoGroupByKey())
   adMatrices = cogroupyresult | 'Matrix addition of grouped matrices' >> beam.ParDo(AddMatricesFn())
...