Python Directed Graph Topological Sort Error: AttributeError: 'Directed_Graph' object has no attribute 'topological_order'

I apologize for the error in my previous response. It seems that I made a mistake in the implementation of the topological_sort method. The error message you received indicates that the DirectedGraph object doesn't have an attribute named topological_order.

To fix this issue, we need to define the topological_order list as an instance variable in the DirectedGraph class. Here's the corrected implementation:

class DirectedGraph:
    def __init__(self):
        self.graph = {}
        self.topological_order = []  # Define topological_order as an instance variable

    # Rest of the methods...

    def topological_sort(self):
        visited = set()

        def dfs(vertex):
            visited.add(vertex)
            neighbors = self.get_neighbors(vertex)
            if neighbors:
                for neighbor in neighbors:
                    if neighbor not in visited:
                        dfs(neighbor)
            self.topological_order.append(vertex)

        for vertex in self.graph:
            if vertex not in visited:
                dfs(vertex)

        self.topological_order.reverse()
        for index, vertex in enumerate(self.topological_order):
            print(f'Vertex: {vertex}, Topological Order: {index + 1}')

    # Rest of the methods...

Make sure to update your code with this corrected implementation, and the error should be resolved. Please let me know if you have any further questions!