Let $D$ be quaternion algebra over a number field $F$. Let $\Delta\subseteq D$ be a maximal $\mathcal{O}_{F}$-order. Let $\mathfrak{b}$ be a fractional left $\Delta$-ideal. In his book "Maximal Orders", I. Reiner defines the 'inverse' of a full left $\mathcal{O}_{F}$-lattice $L$ (which every fractional $\Delta$-ideal also is) as
$L^{-1}:=\{ x \in D : L x L \subseteq L \}.$
How can I compute the inverse of $\mathfrak{b}$ according to Reiner's definition using the MAGMA?