docs: def convert_pathway_mapping(self, other_pathway_mapping):
          """Used to convert the pathway-to-vertex id mapping in one CoNetwork
          to the one used in the current CoNetwork (`self`).
          The following tasks are carried out in the remapping:
          (1) If `self.pathways` contains the pathway to be merged, map the
              vertex id in `other_pathway_mapping` to the vertex id
              in `self.pathways`.
          (2) If not, create a vertex in `self` and then add the key-value pair
              to `self.pathways` accordingly.
  
          Parameters
          -----------
          other_pathway_mapping : dict(str -> int)
            the `pathways` field in the CoNetwork class. This is a
            (pathway -> vertex id) map.
  
          Returns
          -----------
          dict(int -> int), the (other vertex id -> `self` vertex id)
            conversion map
          """
          vertex_id_conversion = {}
          for pathway, vertex_id in other_pathway_mapping.items():
              if pathway in self.pathways:
                  vertex_id_conversion[vertex_id] = self.pathways[pathway]
              else:
                  self_vertex_id = self.add_pathway(pathway)
                  self.vertices[self_vertex_id] = Vertex(self_vertex_id)
                  vertex_id_conversion[vertex_id] = self_vertex_id
          return vertex_id_conversion