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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 sign_items(self, sign_with):
 """ Sign the items in the cart with a GPG key. After everything is collected and signed all the cart items are issued a refresh() to sync their is_signed attributes. `sign_with` is a reference to the method that implements juicer.common.RpmSignPlugin. """

        cart_items = self.items()
        item_paths = [item.path for item in cart_items]
        sign_with(item_paths)

        for item in cart_items:
            item.refresh()