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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 _step_end(self, log=True):
 """ Log end of a step """

        if log:
            step_end_time = self.log(u"STEP %d END (%s)" % (self.step_index, self.step_label))
            diff = (step_end_time - self.step_begin_time)
            diff = float(diff.seconds + diff.microseconds / 1000000.0)
            self.step_total += diff
            self.log(u"STEP %d DURATION %.3f (%s)" % (self.step_index, diff, self.step_label))
            self.step_index += 1