code: def check_switch_vendor(old_vendor, name, urls, _depth=0):
      
      if _depth > 3:
          # Protect against recursive things vendors here.
          return ""
      new_name = check_for_launchpad(old_vendor, name, urls)
      if new_name:
          return "launchpad", new_name
      return "", ""
docs: Check if the project should switch vendors. E.g
      project pushed on pypi, but changelog on launchpad.
  
      :param name: str, name of the project
      :param urls: set, urls to check.
      :return: tuple, (str(new vendor name), str(new project name))