docs: def connect_to(self, vertex, weight=1):
          """
          Connect this vertex to another one.
  
          Args:
              vertex (Vertex): vertex to connect to.
              weight (int): weight of the edge.
  
          Returns:
              Edge: the newly created edge.
          """
          for edge in self.edges_out:
              if vertex == edge.vertex_in:
                  return edge
          return Edge(self, vertex, weight)