Testcase failed: BLPOP on string value

How should we handle it if a BLPOP operation is called on a key which stored a string value previously?
The testcases are as follows:
SET mango banana
BLPOP mango 0.3
Are we to assume the BLPOP operation changes the type of the value stored at key mango, to a list instead?

Hey @asli-nobita, looks like you’ve got past the stage #XJ7. Do you happen to remember what was wrong? Would love to see if we can improve the tester / instructions.