InvalidDefinition: There should be one and only one initial state. Your currently have these: []

[fgmacedo]

InvalidDefinition: There should be one and only one initial state. Your currently have these: []

[fgmacedo]

Hi, you need to define one state as the "initial":

from statemachine import StateMachine, State 

class InvoiceStateMachine(StateMachine):
    unpaid = State(InvoiceStatus.UNPAID.value, initial=True)
    paid = State(InvoiceStatus.PAID.value)
    failed = State(InvoiceStatus.FAILED.value)
    pay = unpaid.to(paid) | unpaid.to(failed)

    def on_pay(self, invoice):
        pass

[ye]

Thanks you @fgmacedo that was it!