What is the share of an heir described as a 'partner' when the bequests consist of specific items and amounts?

Primary text

If the testator bequeaths one hundred to one, a house to another, and a slave to a third, and then states that another person is their 'partner' (sharīk), that partner receives half of what each of the original beneficiaries receives. This is because, in this instance, the partner shares individually with each recipient, and partnership necessitates equality, resulting in half the share of each.