wta_ranking.csv are not homogeneous

[benjdv]

wta_rankings_10s.csv has header and others wta_rankings not

$ head -3 wta_rankings_10s.csv
ranking_date,rank,player,points,undefined
20100101,1,200033,9075,15
20100101,2,201336,7800,
$ head -3 wta_rankings_20s.csv
20200106,1,202458,7851,15
20200106,2,201662,5525,18
20200106,3,201594,5462,17

It would probably be better if all files had a header or none