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Prefect Community

Hi, is it posisble to add @flow to existing class methods?
`class API:`
      `@flow`
      `def start(self):`
          `pass`

I am getting TypeError: missing a required argument: 'self' (edited)

Hi! We generally don’t support this. You can do something like

```
from prefect import flow


class Foo:
    @flow
    def hi(self, name):
        print("hi", name)


foo = Foo()
Foo.hi(foo, name="test")```

Thanks how do we add class method a task?

```class Foo:
    @task
    def greetings(self, name):
        print("Hello", name)
    
    @flow
    def hi(self, name):
        print("hi", name)
        self.greetings(name)


foo = Foo()
Foo.hi(foo, name="test")```
This not working..

Is it not a blocker for people who already coded using class methods in existing projects? how it is supported?

We don’t recommend using class methods because statefulness is not guaranteed

For example, if your task is submitted to a worker when it mutates `self.some_attribute` that state will often not be propagated.

A while ago, a user opened a pull request to just immediately error when sometime tries to decorate a class method: <https://github.com/PrefectHQ/prefect/pull/6864>

fwiw from your example…
```
from prefect import flow, task


class Foo:
    @flow
    def hi(self, name):
        print("hi", name)
        Foo.bye(self)

    @task
    def bye(self):
        print("bye")


foo = Foo()
Foo.hi(foo, name="test")```
works

I doubt we will add first-class support here anytime soon as it’s going to cause more confusing behavior than it’s worth.