human
Solve the following python programming problem given the following code:
@ misc.cachedproperty 
def storage(self) : 
    'The storage unit for this engine.

        NOTE(harlowja): the atom argument lookup strategy will change for
        this storage unit after
        :py:func:`~taskflow.engines.base.Engine.compile` has
        completed (since **only** after compilation is the actual structure
        known). Before :py:func:`~taskflow.engines.base.Engine.compile`
        has completed the atom argument lookup strategy lookup will be
        restricted to injected arguments **only** (this will **not** reflect
        the actual runtime lookup strategy, which typically will be, but is
        not always different).
        ' 
    def _scope_fetcher(atom_name) : 
        if self._compiled : 
            return self._runtime.fetch_scopes_for (atom_name) 
else : 
            return None 
return storage.Storage (self._flow_detail, backend = _scope_fetcher._backend, scope_fetcher = _scope_fetcher) 

    
    

    Fix the buggy line: return storage.Storage (self._flow_detail, backend = _scope_fetcher._backend, scope_fetcher = _scope_fetcher)
assistant
#Here is Python program to fix the buggy line: return storage.

return storage.Storage (self._flow_detail, backend = self._backend, scope_fetcher = _scope_fetcher)