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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 register(cls, tag):
 """Decorator to register a new include tag"""

        def dec(func):
            if tag in _LiquidTagsPreprocessor._tags:
                warnings.warn("Enhanced Markdown: overriding tag '%s'" % tag)
            _LiquidTagsPreprocessor._tags[tag] = func
            return func
        return dec