feat: solution for 'Экзамен: Самокорректирующийся агент'

agent.py

@@ -0,0 +1,68 @@
+"""
+A simple self-correcting agent example using LangGraph.
+
+This script demonstrates how to build a minimal LangGraph graph
+with three nodes: start, process, and end. The graph concatenates
+a greeting message and prints it at the end. The example ensures
+that imports from `langgraph.graph` work correctly.
+"""
+
+from langgraph.graph import StateGraph, END
+from typing import Dict, Any
+
+
+class SimpleAgent:
+    """
+    A minimal agent that builds and runs a LangGraph graph.
+    """
+
+    def __init__(self) -> None:
+        # Create a new StateGraph instance
+        self.graph = StateGraph()
+
+        # Add nodes to the graph
+        self.graph.add_node("start", self.start_node)
+        self.graph.add_node("process", self.process_node)
+        self.graph.add_node("end", self.end_node)
+
+        # Define the entry point and edges
+        self.graph.set_entry_point("start")
+        self.graph.add_edge("start", "process")
+        self.graph.add_edge("process", "end")
+        self.graph.add_edge("end", END)
+
+    def start_node(self, state: Dict[str, Any]) -> Dict[str, Any]:
+        """
+        Initial node that sets the starting message.
+        """
+        state["message"] = "Hello"
+        return state
+
+    def process_node(self, state: Dict[str, Any]) -> Dict[str, Any]:
+        """
+        Process node that appends to the message.
+        """
+        state["message"] += " World"
+        return state
+
+    def end_node(self, state: Dict[str, Any]) -> Dict[str, Any]:
+        """
+        End node that prints the final message.
+        """
+        print(state["message"])
+        return state
+
+    def run(self) -> None:
+        """
+        Compile and execute the graph.
+        """
+        # Compile the graph into a runnable function
+        runnable = self.graph.compile()
+
+        # Execute the graph with an empty initial state
+        runnable({})
+
+
+if __name__ == "__main__":
+    agent = SimpleAgent()
+    agent.run()