code: def drop_prior_information(self):
          
          if self.jco is None:
              self.logger.statement("can't drop prior info, LinearAnalysis.jco is None")
              return
          nprior_str = str(self.pst.nprior)
          self.log("removing " + nprior_str + " prior info from jco, pst, and " +
                                              "obs cov")
          #pi_names = list(self.pst.prior_information.pilbl.values)
          pi_names = list(self.pst.prior_names)
          missing = [name for name in pi_names if name not in self.jco.obs_names]
          if len(missing) > 0:
              raise Exception("LinearAnalysis.drop_prior_information(): "+
                              " prior info not found: {0}".format(missing))
          if self.jco is not None:
              self.__jco.drop(pi_names, axis=0)
          self.__pst.prior_information = self.pst.null_prior
          self.__pst.control_data.pestmode = "estimation"
          #self.__obscov.drop(pi_names,axis=0)
          self.log("removing " + nprior_str + " prior info from jco, pst, and " +
                                              "obs cov")
docs: drop the prior information from the jco and pst attributes