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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 is_valid_state(self):

 """A bool value that indicates whether the object's state is a valid 
 state code."""

        return self.is_valid_country and self.country.upper() in STATES and \
               self.state is not None and \
               self.state.upper() in STATES[self.country.upper()]