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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 assign_constant(self, value, dtype=None):
 """ Assign a constant value to all nonzeros in the pianoroll. If the pianoroll is not binarized, its data type will be preserved. If the pianoroll is binarized, it will be casted to the type of `value`. Arguments --------- value : int or float The constant value to be assigned to all the nonzeros in the pianoroll. """

        if not self.is_binarized():
            self.pianoroll[self.pianoroll.nonzero()] = value
            return
        if dtype is None:
            if isinstance(value, int):
                dtype = int
            elif isinstance(value, float):
                dtype = float
        nonzero = self.pianoroll.nonzero()
        self.pianoroll = np.zeros(self.pianoroll.shape, dtype)
        self.pianoroll[nonzero] = value