<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def __contribution_from_parameters(self, parameter_names):
 """private method get the prior and posterior uncertainty reduction as a result of some parameter becoming perfectly known Parameters parameter_names : list parameter that are perfectly known Returns ------- dict : dict dictionary of forecast name, [prior uncertainty w/o parameter_names, % posterior uncertainty w/o parameter names] Note ---- this method is used by get_parameter_contribution() method - don't call this method directly """



        #get the prior and posterior for the base case
        bprior,bpost = self.prior_prediction, self.posterior_prediction
        #get the prior and posterior for the conditioned case
        la_cond = self.get_conditional_instance(parameter_names)
        cprior,cpost = la_cond.prior_prediction, la_cond.posterior_prediction
        return cprior,cpost