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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 relevant_part(self, original, pos, sep=' '):
 """ calculates the subword in a `sep`-splitted list of substrings of `original` that `pos` is ia.n """

        start = original.rfind(sep, 0, pos) + 1
        end = original.find(sep, pos - 1)
        if end == -1:
            end = len(original)
        return original[start:end], start, end, pos - start