conflicted about this; the point of $values = list() is that the previous state of $values is overwritten. $set_values() does not change values that are already set; even if it does the same thing, the information that there is no relevant previous state is lost. In reality, we should probably use the init = functionality of the new paradox syntax. Will leave this open for now and think about it

At some point we will refactor this to use init = in the p_xxx() constructors.