code: def filename_from_webname(self, webname):
          
          if not webname.startswith(self.base_url):
              raise ValueError("Webname doesn't match base_url")
  
          _name = webname[len(self.base_url):]
          if _name.startswith('/'):
              return _name[1:]
          else:
              return _name
docs: A 1<->1 map is maintained between a URL pointing to a file and
          the name of the file in the file system.
  
          As an example if the base_url is 'https://example.com' and a jwks_uri
          is 'https://example.com/jwks_uri.json' then the filename of the
          corresponding file on the local filesystem would be 'jwks_uri'.
          Relative to the directory from which the RP instance is run.
  
          :param webname: The published URL
          :return: local filename