I was working on the qiskit summer school 2023 lab. While I was submitting the answer to grader, suddenly I got a response mentioning _legacy_format_cache error. I restarted the kernel that did not resolve the issue. I signed out of the IBMID and relogged in which also did not resolve the issue. I did not find anything on the web related to this issue. Any clue is welcome.

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    $\begingroup$ From Brian Ingmanson in the discord discussion: "The error _legacy_format_cache in Lab 4 is due to the new version of qiskit. To fix it just install the previous qiskit version with "!pip install qiskit==0.43.2" and reboot the kernel after. It should work." $\endgroup$ Aug 22, 2023 at 7:27


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