code: def addrownumbers(table, start=1, step=1, field='row'):
      
  
      return AddRowNumbersView(table, start, step, field)
docs: Add a field of row numbers. E.g.::
  
          >>> import petl as etl
          >>> table1 = [['foo', 'bar'],
          ...           ['A', 9],
          ...           ['C', 2],
          ...           ['F', 1]]
          >>> table2 = etl.addrownumbers(table1)
          >>> table2
          +-----+-----+-----+
          | row | foo | bar |
          +=====+=====+=====+
          |   1 | 'A' |   9 |
          +-----+-----+-----+
          |   2 | 'C' |   2 |
          +-----+-----+-----+
          |   3 | 'F' |   1 |
          +-----+-----+-----+
  
      Parameters `start` and `step` control the numbering.