code: def storage_keys(self):
          
          if not self._module:
              return []
          self._storage_init()
          module_name = self._module.module_full_name
          return self._storage.storage_keys(module_name)
docs: Return a list of the keys for values stored for the module.
  
          Keys will contain the following metadata entries:
          - '_ctime': storage creation timestamp
          - '_mtime': storage last modification timestamp