It fully works but not clean enought

src/crewai/flow/flow.py

@@ -1,4 +1,4 @@
-from typing import Any, Callable, Dict, Generic, List, TypeVar, Union, get_args
+from typing import Any, Callable, Dict, Generic, List, Type, TypeVar, Union, get_args
 
 from pydantic import BaseModel
 
@@ -32,6 +32,7 @@ class Flow(Generic[TState], metaclass=FlowMeta):
     _start_methods: List[str] = []
     _listeners: Dict[str, List[str]] = {}
     state: TState
+    state_class: Type[TState]
 
     def __init__(self):
         self._methods: Dict[str, Callable] = {}
@@ -44,18 +45,15 @@ class Flow(Generic[TState], metaclass=FlowMeta):
                 self._methods[method_name] = getattr(self, method_name)
 
     def _create_default_state(self) -> TState:
-        state_type = self._get_state_type()
+        if not hasattr(self, "state_class"):
-        if state_type and issubclass(state_type, BaseModel):
+            raise AttributeError("state_class must be defined in the Flow subclass")
-            return state_type()
-        return DictWrapper()  # type: ignore
 
-    def _get_state_type(self) -> type[TState] | None:
+        if issubclass(self.state_class, BaseModel):
-        for base in self.__class__.__bases__:
+            return self.state_class()
-            if hasattr(base, "__origin__") and base.__origin__ is Flow:
+        elif self.state_class is dict:
-                args = get_args(base)
+            return DictWrapper()  # type: ignore
-                if args:
+        else:
-                    return args[0]
+            raise TypeError(f"Unsupported state type: {self.state_class}")
-        return None
 
     def run(self):
         if not self._start_methods:

src/crewai/flow/structured_test_flow.py

@@ -8,17 +8,27 @@ class ExampleState(BaseModel):
 
 
 class StructuredExampleFlow(Flow[ExampleState]):
+    state_class = ExampleState
+
+    def __init__(self):
+        super().__init__()
+        print(f"Initial state after __init__: {self.state}")  # Debug print
+
     @start()
     def start_method(self):
         print("Starting the structured flow")
+        print(f"State in start_method: {self.state}")  # Debug print
         self.state.message = "Hello from structured flow"
+        print(f"State after start_method: {self.state}")  # Debug print
         return "Start result"
 
     @listen(start_method)
     def second_method(self, result):
         print(f"Second method, received: {result}")
+        print(f"State before increment: {self.state}")  # Debug print
         self.state.counter += 1
-        self.state.message = "Hello from structured flow"
+        self.state.message += " - updated"
+        print(f"State after second_method: {self.state}")  # Debug print
         return "Second result"