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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 _initialize_initial_state_fluents(self):
        '''Returns the initial state-fluents instantiated.'''
        state_fluents = self.rddl.domain.state_fluents
        initializer = self.rddl.instance.init_state
        self.initial_state_fluents = self._initialize_pvariables(
            state_fluents,
            self.rddl.domain.state_fluent_ordering,
            initializer)
        return self.initial_state_fluents