Add: multiple fallback tutorial

tutorials/script/core/10_multiple_fallback_nodes.py

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+# %% [markdown]
+"""
+# Core: 10. Multiple fallback nodes
+
+This tutorial shows basics of creating a separate fallback node for every flow. In this case it is done via `LOCAL` nodes.
+
+Let's do all the necessary imports from DFF:
+"""
+
+# %pip install dff
+
+
+"""Importing all the necessary modules:"""
+
+# %%
+from dff.pipeline import Pipeline
+from dff.script import TRANSITIONS, RESPONSE, Message, LOCAL
+import dff.script.conditions as cnd
+
+# %% [markdown]
+"""
+Let's create a script that will consist of several flows, that can be accessed through dialogue:
+"""
+
+# %%
+toy_script = {
+    "greeting_flow": {
+        "start_node": {
+            RESPONSE: Message(),
+            TRANSITIONS: {
+                ("greeting_flow", "say_hi_node"): cnd.true()
+            }
+        },
+
+        "say_hi_node": {
+            RESPONSE: Message(text="Hello, how can I help you?"),
+            TRANSITIONS: {
+                ("authorization_flow", "response_node"): cnd.exact_match(Message(text="/auth")),
+                ("information_flow", "response_node"): cnd.exact_match(Message(text="/info"))
+            }
+        },
+
+        "fallback_node": {
+            RESPONSE: Message(text="Unknown Command. Try again."),
+            TRANSITIONS: {"say_hi_node": cnd.exact_match(Message(text="hi"))
+            }
+        }
+    },
+    "authorization_flow": {
+        LOCAL: {
+            TRANSITIONS: {
+                ("auth_fallback_node", 0.1):
+                    cnd.true()
+            }
+        },
+        "response_node": {
+            RESPONSE: Message(text="Write your name, please."),
+            TRANSITIONS: {
+                ("authorization_flow", "auth_password_node"):
+                    cnd.exact_match(Message(text="admin")),
+                ("authorization_flow", "auth_success_node"):
+                    cnd.exact_match(Message(text="John Doe"))
+            }
+        },
+
+        "auth_success_node": {
+            RESPONSE: Message(text="Authentication successful."),
+            TRANSITIONS: {
+                ("greeting_flow", "start_node"):
+                    cnd.true()
+            }
+        },
+
+        "auth_password_node": {
+            RESPONSE: Message(text="Password required. Enter your password."),
+            TRANSITIONS: {
+                ("authorization_flow", "auth_success_node"):
+                    cnd.exact_match(Message(text="123"))
+            }
+        },
+
+        "auth_fallback_node": {
+            RESPONSE: Message(text="User is not found or password is incorrect."),
+            TRANSITIONS: {
+                ("greeting_flow", "say_hi_node"):
+                    cnd.true()
+            }
+        }
+    },
+
+    "information_flow": {
+        LOCAL: {
+            TRANSITIONS: {
+                ("information_fallback_node", 0.1):
+                    cnd.true()
+            }
+        },
+        "response_node": {
+            RESPONSE: Message(text="What information you would like to know?"),
+            TRANSITIONS: {
+                ("information_flow", "weather_city_node"):
+                    cnd.exact_match(Message(text="weather")),
+                ("information_flow", "time_node"):
+                    cnd.exact_match(Message(text="time"))
+            }
+        },
+        "weather_city_node": {
+            RESPONSE: Message(text="What city are interested in?"),
+            TRANSITIONS: {
+                ("information_flow", "weather_moscow_node"):
+                    cnd.exact_match(Message(text="Moscow")),
+                ("information_flow", "weather_new_york_node"):
+                    cnd.exact_match(Message(text="New York"))
+            }
+        },
+        "weather_moscow_node": {
+            RESPONSE: Message(text="It's -5 Celsius"),
+            TRANSITIONS: {
+                ("greeting_flow", "start_node"): cnd.true()
+                }
+        },
+        "weather_new_york_node": {
+            RESPONSE: Message(text="It's +14 Celsius"),
+            TRANSITIONS: {
+                ("greeting_flow", "start_node"): cnd.true()
+                }
+        },
+        "time_node": {
+            RESPONSE: Message(text="It's tea time!"),
+            TRANSITIONS: {
+                ("greeting_flow", "start_node"):
+                    cnd.true()
+            }
+        },
+        "information_fallback_node": {
+            RESPONSE: Message(text="I don't know that information!"),
+            TRANSITIONS: {
+                ("information_flow", "response_node"):
+                    cnd.true()
+            }
+        }
+    }
+}
+
+# %% [markdown]
+"""
+As you can see, we've created specific fallback node for each individual flow using `LOCAL` node. Due to the low priority (explicitly set as `0.1`) this condition will trigger automatically if no other condition in any node in the flow was triggered.
+Also we defined `fallback_label` in our `Pipeline` which is being overwritten with `LOCAL` nodes in flows they defined in.
+
+And now let's run our script:
+"""
+# %%
+pipeline = Pipeline.from_script(
+    toy_script,
+    start_label=("greeting_flow", "start_node"),
+    fallback_label=("greeting_flow", "fallback_node")
+    )
+
+if __name__ == "__main__":
+    pipeline.run()