code: def _parse_pi_par_names(self):
          
          if self.prior_information.shape[0] == 0:
              return
          if "names" in self.prior_information.columns:
              self.prior_information.pop("names")
          if "rhs" in self.prior_information.columns:
              self.prior_information.pop("rhs")
          def parse(eqs):
              raw = eqs.split('=')
              rhs = float(raw[1])
              raw = [i for i in re.split('[###]',
                      raw[0].lower().strip().replace(' + ','###').replace(' - ','###')) if i != '']
              # in case of a leading '-' or '+'
              if len(raw[0]) == 0:
                  raw = raw[1:]
              # pnames = []
              # for r in raw:
              #     if '*' not in r:
              #         continue
              #     pname =  r.split('*')[1].replace("log(", '').replace(')', '').strip()
              #     pnames.append(pname)
              # return pnames
              return [r.split('*')[1].replace("log(",'').replace(')','').strip() for r in raw if '*' in r]
  
          self.prior_information.loc[:,"names"] =\
              self.prior_information.equation.apply(lambda x: parse(x))
docs: private method to get the parameter names from prior information
          equations.  Sets a 'names' column in Pst.prior_information that is a list
          of parameter names