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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 Detect(self, progs):
 """Return the first available program in progs. """

        if not SCons.Util.is_List(progs):
            progs = [ progs ]
        for prog in progs:
            path = self.WhereIs(prog)
            if path: return prog
        return None