docs: def _add_edge_to_vertex(self, vertex_id, edge):
          """Adds the edge to the Vertex object's `edges` dictionary
          """
          connected_to = edge.connected_to(vertex_id)
          if vertex_id not in self.vertices:
              vertex_obj = Vertex(vertex_id)
              self.vertices[vertex_id] = vertex_obj
          self.vertices[vertex_id].edges[connected_to] = edge.weight