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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 get_as_list(self, tag_name):
 """ Return the value of a tag, making sure that it's a list. Absent tags are returned as an empty-list; single tags are returned as a one-element list. The returned list is a copy, and modifications do not affect the original object. """

        val = self.get(tag_name, [])
        if isinstance(val, list):
            return val[:]
        else:
            return [val]