code: def component_doi(soup):
      
      component_doi = []
  
      object_id_tags = raw_parser.object_id(soup, pub_id_type = "doi")
  
      # Get components too for later
      component_list = components(soup)
  
      position = 1
  
      for tag in object_id_tags:
          component_object = {}
          component_object["doi"] = doi_uri_to_doi(tag.text)
          component_object["position"] = position
  
          # Try to find the type of component
          for component in component_list:
              if "doi" in component and component["doi"] == component_object["doi"]:
                  component_object["type"] = component["type"]
  
          component_doi.append(component_object)
  
          position = position + 1
  
      return component_doi
docs: Look for all object-id of pub-type-id = doi, these are the component DOI tags