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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 sliding(self, size, step=1):
 """ Groups elements in fixed size blocks by passing a sliding window over them. The last window has at least one element but may have less than size elements :param size: size of sliding window :param step: step size between windows :return: sequence of sliding windows """

        return self._transform(transformations.sliding_t(_wrap, size, step))