code: def _get_token_from_headers(self, request, refresh_token):
          
          header = request.headers.get(self.config.authorization_header(), None)
  
          if header is None:
              return None
  
          else:
              header_prefix_key = "authorization_header_prefix"
              header_prefix = getattr(self.config, header_prefix_key)
              if header_prefix():
                  try:
                      prefix, token = header.split(" ")
                      if prefix != header_prefix():
                          raise Exception
  
                  except Exception:
                      raise exceptions.InvalidAuthorizationHeader()
  
              else:
                  token = header
  
              if refresh_token:
                  token = request.json.get(self.config.refresh_token_name())
  
              return token
docs: Extract the token if present inside the headers of a request.