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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 walk(self, fn):
 """ Loops through all data elements and allows a function to interact with each data element. Uses a generator to improve iteration. :param fn: Function that interacts with each DICOM element """

        if not hasattr(fn, "__call__"):
            raise TypeError("""walk_dataset requires a
                function as its parameter""")

        dataset = self._dataset
        iterator = dataset.GetDES().begin()
        while (not iterator.equal(dataset.GetDES().end())):
            data_element = iterator.next()
            yield fn(data_element)

        header = self._header
        iterator = header.GetDES().begin()
        while (not iterator.equal(header.GetDES().end())):
            data_element = iterator.next()
            yield fn(data_element)