# Computing ideals of a given norm in Quaternion algebra

Let $B$ be the quaternion algebra over $\mathbb{Q}$ ramified at prime $p$ and $\infty$ and $\mathcal{O}\subset B$ be a maximal order. How do you compute all integral right ideals $ I \subseteq \mathcal{O}$ of a given norm?

Say $l$ is prime. You know `BrandtModule(p).hecke_matrix(l)`

returns $l$-Brandt matrix of B and we can draw the $l$-Brandt graph from it, then $\mathcal{O}$ is a vertex and there are $l+1$ integral right $\mathcal{O}$-ideals of norm $l$ representing each of edge from $\mathcal{O}$ in general. I'd like to compute these $l$-neighbors of $\mathcal{O}$.