[Python] Why the Condition in the Langraph is not working

I am trying to build a langraph and call the relevant node as per the condition, this is my code

class PersonDetails(TypedDict):
name: str
age: int

# Nodes
def greet(state: PersonDetails):
print(f"Hello, {state['name']}!")
return state

def check_age(state: PersonDetails):
age = state['age']
if age >= 21:
return "can_drink"
elif age >= 16:
return "can_drive"
else:
return "minor"
# return state

def can_drink(state: PersonDetails):
print("You can legally drink ")
return state

def can_drive(state: PersonDetails):
print("You can drive ")
return state

def minor(state: PersonDetails):
print("You're a minor ")
return state

# Build graph
graph = StateGraph(PersonDetails)
graph.add_node("greet", greet)
graph.add_node("check_age", RunnableLambda(check_age)) # must wrap conditional node
graph.add_node("can_drink", can_drink)
graph.add_node("can_drive", can_drive)
graph.add_node("minor", minor)

# Edges
graph.add_edge(START, "greet")
graph.add_edge("greet", "check_age")
# graph.add_edge("check_age", END)

# Conditional branching
graph.add_conditional_edges(
"check_age",
{
"can_drink": "can_drink",
"can_drive": "can_drive",
"minor": "minor"
}
)

graph.add_edge("can_drink", END)
graph.add_edge("can_drive", END)
graph.add_edge("minor", END)

# Compile graph
app = graph.compile()


but when i run this code, i am getting error like this

TypeError: Expected a Runnable, callable or dict.Instead got an unsupported type: <class 'str'>
​

not able to know what exactly i am doing wrong, can anyone guide me on this

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