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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def schema_complete():
 """Schema for data in CollectorStage."""

        return Schema({
            'stage': And(str, len),
            'status': And(str, lambda s: s in ['started', 'succeeded', 'failed']),
            Optional('events', default=[]): And(len, [CollectorStage.schema_event_items()])
        })