def executed_branch_arcs(self) -> dict[TLineNo, list[TLineNo]]:
        """Return arcs that were executed from branch lines.

        Only include ones that we considered possible.

        Returns {l1:[l2a,l2b,...], ...}

        """
        branch_lines = set(self._branch_lines())
        eba = collections.defaultdict(list)
        for l1, l2 in self.arcs_executed:
            assert l1 != l2, f"Oops: Didn't think this could happen: {l1 = }, {l2 = }"
            if (l1, l2) not in self.arc_possibilities_set:
                continue
            if l1 in branch_lines:
                eba[l1].append(l2)
        return eba
Return arcs that were executed from branch lines.

        Only include ones that we considered possible.

        Returns {l1:[l2a,l2b,...], ...}

        
coverage/results.py