code: def get_resources_chunk(self, resource_iter, first=None):
          
          chunk = ListBase(md=self.md.copy(), ln=list(self.ln))
          chunk.capability_name = self.capability_name
          chunk.default_capability()
          if (first is not None):
              chunk.add(first)
          for r in resource_iter:
              chunk.add(r)
              if (len(chunk) >= self.max_sitemap_entries):
                  break
          # Get next to see whether there are more resources
          try:
              nxt = next(resource_iter)
          except StopIteration:
              nxt = None
          return(chunk, nxt)
docs: Return next chunk of resources from resource_iter, and next item.
  
          If first parameter is specified then this will be prepended to
          the list.
  
          The chunk will contain self.max_sitemap_entries if the iterator
          returns that many. next will have the value of the next value from
          the iterator, providing indication of whether more is available.
          Use this as first when asking for the following chunk.