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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 is_end(self, char):
 """ Return `True` if this `char` is part of this node's letter set, `False` otherwise. """

        char = char.lower()

        return bool(cgaddag.gdg_is_end(self.gdg, self.node, char.encode("ascii")))