'Remove key out of option stores. This operation must succeed on the
database first. If database fails, an exception is raised.
If database succeeds, caches are then allowed to fail silently.
A boolean is returned to indicate if the network deletion succeeds.'

def delete(self, key):

    assert (self.cache is not None), 'cache    must    be    configured    before    mutating    options'
    self.delete_store(key)
    return self.delete_cache(key)
