project test "Test" "1.0" 2007-08-20 +2m 

shift a "A" {
	workinghours mon - fri off
}
shift b "B" {
	workinghours mon - fri 10:00 - 18:00
}

resource r "R" {
	shifts a 2007-08-20 +2w
# MARK: error 13 shift_assignment_overlap 
	shifts b 2007-09-01 +2w
}