code: def base_mortality_rate(self, index: pd.Index) -> pd.Series:
          
          return pd.Series(self.config.mortality_rate, index=index)
docs: Computes the base mortality rate for every individual.
  
          Parameters
          ----------
          index :
              A representation of the simulants to compute the base mortality
              rate for.
  
          Returns
          -------
              The base mortality rate for all simulants in the index.