code: def _rc_renamenx(self, src, dst):
          "Rename key ``src`` to ``dst`` if ``dst`` doesn't already exist"
          if self.exists(dst):
              return False
  
          return self._rc_rename(src, dstf _rc_renamenx(self, src, dst):
          "Rename key ``src`` to ``dst`` if ``dst`` doesn't already exist"
          if self.exists(dst):
              return False
  
          return self._rc_rename(src, dst)
docs: Rename key ``src`` to ``dst`` if ``dst`` doesn't already exist