# Define the nodes

def node_a(state: State) -> Command[Literal["node_b", "node_c"]]:
    print("Called A")
    value = random.choice(["b", "c"])
    # this is a replacement for a conditional edge function
    if value == "b":
        goto = "node_b"
    else:
        goto = "node_c"

    # note how Command allows you to BOTH update the graph state AND route to the next node
    return Command(
        # this is the state update
        update={"foo": value},
        # this is a replacement for an edge
        goto=goto,
    )

def node_b(state: State):
    print("Called B")
    return {"foo": state["foo"] + "b"}

def node_c(state: State):
    print("Called C")
    return {"foo": state["foo"] + "c"}
```

We can now create the `StateGraph` with the above nodes. Notice that the graph doesn't have [conditional edges](../concepts/low_level.md#conditional-edges) for routing! This is because control flow is defined with `Command` inside `node_a`.

```python
builder = StateGraph(State)
builder.add_edge(START, "node_a")
builder.add_node(node_a)
builder.add_node(node_b)
builder.add_node(node_c)