code: def _get_client_address(self, req):
          
          try:
              forwarded_for = req.get_header('X-Forwarded-For', True)
              return forwarded_for.split(',')[0].strip()
          except (KeyError, HTTPMissingHeader):
              return (
                  req.env.get('REMOTE_ADDR') if self.remote_address_fallback
                  else None
              )
docs: Get address from ``X-Forwarded-For`` header or use remote address.
  
          Remote address is used if the ``X-Forwarded-For`` header is not
          available. Note that this may not be safe to depend on both without
          proper authorization backend.
  
          Args:
              req (falcon.Request): falcon.Request object.
  
          Returns:
              str: client address.