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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 incrby(self, key, increment):
 """Increment the integer value of a key by the given amount. :raises TypeError: if increment is not int """

        if not isinstance(increment, int):
            raise TypeError("increment must be of type int")
        return self.execute(b'INCRBY', key, increment)