square/pylink

AI Summary: The task is to fix a bug in the `pylink` library where the `JLink.flash()` method raises the wrong exception (`JLinkEraseException`) when `JLINKARM_EndDownload()` returns an error code. The correct exception type needs to be determined and raised based on the specific error code returned by `JLINKARM_EndDownload()`. This involves examining the error codes (-1, -2, -3, -4) and mapping them to the appropriate exception types within the `pylink` library.