release(node, inner) {
        const scopes = this.__get(node);

        if (scopes && scopes.length) {
            const scope = scopes[0].upper;

            if (!scope) {
                return null;
            }
            return this.acquire(scope.block, inner);
        }
        return null;
    }
release the node.
@function ScopeManager#release
@param {Espree.Node} node releasing node.
@param {?boolean} [inner=false] look up the most inner scope, default value is false.
@returns {Scope?} upper scope for the node.