178. Rank Scores

Test case- {"headers": {"Scores": ["Id", "Score"]}, "rows": {"Scores": [[null,null]]}}

for the above test case I feel like the possible input could be [null,null] as no where mentioned in the problem that the id is primary-key.
So, here output should be- [null,null] because input denotes there is no data. So, no rank should get assigned to this.
But I am getting output as- [null,1].

Please let me know if my assumptions are correct?