This method inserts values into the table specified filling in the values from the dictionary. It then reloads the dictionary with the values from the database. This causes the dictionary to be updated with values that are modified by rules, triggers, etc.
Due to the way that this function works you will find inserts taking longer and longer as your table gets bigger. To overcome this problem simply add an index onto the OID of any table that you think may get large over time.
Read the upstream documentation. For corrections, first check the current manual.