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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 get_rpndict_flag(self, rpndict):
 """ calculate flag set, the value is True or False, if rpndict value is not None, flag is True, or False if set with only one item, i.e. True returns, means values of rpndict are all valid float numbers, then finally return True, or False """

        flag_set = set([rpn.Rpn.solve_rpn(str(v)) is not None for v in rpndict.values()])
        if len(flag_set) == 1 and flag_set.pop():
            return True
        else:
            return False