In reply to 8Blades:
Never raise objections in pre_body() or drop objections in post_body(). Doing this will have a significant detrimental impact on your simulation performance. Instead, only raise and lower objections at the test level.
You can use pre_body() to do any data initialization that might be necessary for your sequence item. You can use post_body() to do any calculations on the randomized data such as checksum and parity fields.