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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_parent(self, tree, alt=None):
 """ Get parent for given `tree` or `alt` if not found. Args: tree (obj):
 :class:`.Tree` instance, which is already stored in DB. alt (obj, default None):
 Alternative value returned when `tree` is not found. Returns: obj: :class:`.Tree` parent to given `tree`. """

        parent = self.parent_db.get(tree.path)

        if not parent:
            return alt

        return list(parent)[0]