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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 global_get(self, key):
 """Return the value for the given key in the ``globals`` table."""

        key = self.pack(key)
        r = self.sql('global_get', key).fetchone()
        if r is None:
            raise KeyError("Not set")
        return self.unpack(r[0])