ct/py/test_data/csv_pivot_table_merger/three_entries.csv

page_set,stories,name,avg,run_index,unit,pct_001
,,x,x4.1,0,,
,,y,y4.1,0,,
,,z,z4.1,0,,
,,x,x4.2,1,,
,,y,y4.2,1,,
,,z,z4.2,1,,
,,x,x4.3,2,,
,,y,y4.3,2,,
,,z,z4.3,2,,