def findCachedDomain(self, var_cache_id, region, dataset=None ):
cached_var = self.cachedVariables.get( var_cache_id, None )
if cached_var == None:
cached_var = CachedVariable( id=var_cache_id, dataset=dataset)
self.cachedVariables[ var_cache_id ] = cached_var
overlap,domain = cached_var.findDomain( region )
if overlap == Domain.CONTAINED: return cached_var, domain
return cached_var, None
