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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 fast(self):
 """Access the 'fast' dimension This mode yields iline or xline mode, depending on which one is laid out `faster`, i.e. the line with linear disk layout. Use this mode if the inline/crossline distinction isn't as interesting as traversing in a fast manner (typically when you want to apply a function to the whole file, line-by-line). Returns ------- fast : Line line addressing mode Notes ----- .. versionadded:: 1.1 """

        if self.sorting == TraceSortingFormat.INLINE_SORTING:
            return self.iline
        elif self.sorting == TraceSortingFormat.CROSSLINE_SORTING:
            return self.xline
        else:
            raise RuntimeError("Unknown sorting.")