cube method
Implementation
List<AST> cube(List<Expr> variables, int backtrackLevel) {
final variablesVec = _c._packAstVector(variables);
_c._z3.ast_vector_inc_ref(variablesVec);
final result = _c._unpackAstVector(_c._z3.solver_cube(
_solver,
variablesVec,
backtrackLevel,
));
_c._z3.ast_vector_dec_ref(variablesVec);
return result.cast();
}