code: def absolute_uri(self, location=None, scheme=None, **query):
          
          if not is_absolute_uri(location):
              if location or location is None:
                  location = self.full_path(location, **query)
              if not scheme:
                  scheme = self.is_secure and 'https' or 'http'
              base = '%s://%s' % (scheme, self.get_host())
              return '%s%s' % (base, location)
          elif not scheme:
              return iri_to_uri(location)
          else:
              raise ValueError('Absolute location with scheme not valid')
docs: Builds an absolute URI from ``location`` and variables
          available in this request.
  
          If no ``location`` is specified, the relative URI is built from
          :meth:`full_path`.