def _compute_all_deletions(self):
        """Returns all minimal edge covers of the set of evil edges.
        """
        minimum_evil = []
        for disabled_qubits in map(set, product(*self._evil)):
            newmin = []
            for s in minimum_evil:
                if s < disabled_qubits:
                    break
                elif disabled_qubits < s:
                    continue
                newmin.append(s)
            else:
                minimum_evil = newmin + [disabled_qubits]
        return minimum_evil
Returns all minimal edge covers of the set of evil edges.