'a fast expire that can be called by column loaders during a load.
The additional bookkeeping is finished up in commit_all().
Should only be called for scalar attributes.
This method is actually called a lot with joined-table
loading, when the second table isn\'t present in the result.'

def _expire_attribute_pre_commit(self, dict_, key):

    dict_.pop(key, None)
    self.callables[key] = self
