code: def dep(self, source_name):
          
          from ambry.orm.exc import NotFoundError
          from ambry.dbexceptions import ConfigurationError
  
          source = self.source(source_name)
  
          ref = source.url
  
          if not ref:
              raise ValueError("Got an empty ref for source '{}' ".format(source.name))
  
          try:
              try:
  
                  p = self.library.partition(ref)
              except NotFoundError:
  
                  self.warn("Partition reference {} not found, try to download it".format(ref))
                  remote, vname = self.library.find_remote_bundle(ref, try_harder=True)
                  if remote:
                      self.warn("Installing {} from {}".format(remote, vname))
                      self.library.checkin_remote_bundle(vname, remote)
                      p = self.library.partition(ref)
                  else:
                      raise
  
              if not p.is_local:
                  with self.progress.start('test', 0, message='localizing') as ps:
                      p.localize(ps)
  
              return p
  
          except NotFoundError:
              return self.library.bundle(ref)
docs: Return a bundle dependency from the sources list
  
          :param source_name: Source name. The URL field must be a bundle or partition reference
          :return: