type does not provide a call operator

I have this function, order, which returns vector<Node*>

vector<Node*> order(vector<string> nodes, vector<pair<string, string>> dependencies) {
             Graph graph = buildGraph(nodes, dependencies);
             vector<Node*> order = buildOrder(graph.getNodes());
             return order;
}

and I call it like this:

vector<Node*> order2 = order(nodes, deps);

However, the compiler gives this error:

error: type 'std::__1::vector<Node *, std::__1::allocator<Node *> >' does not provide a call operator
        vector<Node*> order2 = order(nodes, deps);
                               ^~~~~
1 error generated.

What is going wrong? 'std::__1::vector<Node *, std::__1::allocator<Node *> >' seems to suggest that there is a vector<Node*, <Node*>> or something going on, but I can't seem to figure this out.