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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 b_pathOK(self, al_path):
 """ Checks if the absolute path specified in the al_path is valid for current tree """

            b_OK  = True
            try:          self.l_allPaths.index(al_path)
            except:       b_OK    = False
            return b_OK