code: def sitemap_uri(self, basename):
          
          if (re.match(r"\w+:", basename)):
              # looks like URI
              return(basename)
          elif (re.match(r"/", basename)):
              # looks like full path
              return(basename)
          else:
              # build from mapping with name appended
              return(self.mapper.default_src_uri() + '/' + basename)
docs: Get full URI (filepath) for sitemap based on basename.