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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 relabel_consecutive(self, start_label=1):
 """ Reassign the label numbers consecutively, such that there are no missing label numbers. Parameters start_label : int, optional The starting label number, which should be a positive integer. The default is 1. Examples -------- array([[1, 1, 0, 0, 3, 3], [0, 0, 0, 0, 0, 3], [0, 0, 2, 2, 0, 0], [5, 0, 0, 0, 0, 4], [5, 5, 0, 4, 4, 4], [5, 5, 0, 0, 4, 4]]) """


        if start_label <= 0:
            raise ValueError('start_label must be > 0.')

        if self.is_consecutive and (self.labels[0] == start_label):
            return

        new_labels = np.zeros(self.max_label + 1, dtype=np.int)
        new_labels[self.labels] = np.arange(self.nlabels) + start_label
        self.data = new_labels[self.data]