You are right
from cmk.utils.aws_constants import (
AWSRegions,
AWSEC2InstFamilies,
AWSEC2InstTypes,
AWSEC2LimitsDefault,
AWSEC2LimitsSpecial,
)
but this
/opt/omd/sites/sitename/lib/check_mk/utils/aws_constants.py
is the only part I can ident in the Code so it should work
perhaps @martin.schwarz has an other Idea