Interviewed at multiple places and received immediate job offer from one. Is it bad form to contact the other place(s) where still under review?

So I had multiple interviews, and one place fairly quickly offered me a position.

My ideal place says there's a 7 day post interview period where the owners decide if they want you to come in for a 2nd interview.

Would it be bad form for me to immediately email them? I had the email typed and ready to fire, but wonder if this could back-fire on me.

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