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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 Split(self, arg):
 """This function converts a string or list into a list of strings or Nodes. This makes things easier for users by allowing files to be specified as a white-space separated list to be split. The input rules are: - A single string containing names separated by spaces. These will be split apart at the spaces. - A single Node instance - A list containing either strings or Node instances. Any strings in the list are not split at spaces. In all cases, the function returns a list of Nodes and strings."""


        if SCons.Util.is_List(arg):
            return list(map(self.subst, arg))
        elif SCons.Util.is_String(arg):
            return self.subst(arg).split()
        else:
            return [self.subst(arg)]