[Python] Regex: how to match all strings except when the pattern occurs at a specific position

I have a problem that would benefit greatly if I can include all matches of a pattern that do not occur at one specific index in a string. For example, if I want to match "ABC", except when it occurs in the 4th position of the string, I would need the following results:

• ABCDEFGH (Match)
• HABCDEFG (Match)
• GHABCDEF (Match)
• FGHABCDE (Don't Match)
• EFGHABCD (Match)

I have been reading about negative lookaheads and negative lookbehinds for a while now and cannot seem to find an example that fits my use case. Any help with this would be extremely appreciated.

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