key1,key2,data4,data5
A,1,A1d4,A1d5
A,2,A2d4,A2d5
B,1,B1d4,B1d5
A,2,A2d4bis,A2d5bis
A,2,A2d4ter,A2d5ter
B,1,B1d4bis,B1d5bis