code: def get_values(self, variables = None, table = None, lowercase = False, rename_ident = True):
          
          assert self.hdf5_file_path is not None
          assert os.path.exists(self.hdf5_file_path), '{} is not a valid path'.format(
              self.hdf5_file_path)
          store = pandas.HDFStore(self.hdf5_file_path)
  
          try:
              df = store.select(table)
          except KeyError:
              log.error('No table {} in the file {}'.format(table, self.hdf5_file_path))
              log.error('Table(s) available are: {}'.format(store.keys()))
              store.close()
              raise
  
          if lowercase:
              columns = dict((column_name, column_name.lower()) for column_name in df)
              df.rename(columns = columns, inplace = True)
  
          if rename_ident is True:
              for column_name in df:
                  if ident_re.match(str(column_name)) is not None:
                      df.rename(columns = {column_name: "ident"}, inplace = True)
                      log.info("{} column have been replaced by ident".format(column_name))
                      break
  
          if variables is None:
              return df
          else:
              diff = set(variables) - set(df.columns)
              if diff:
                  raise Exception("The following variable(s) {} are missing".format(diff))
              variables = list(set(variables).intersection(df.columns))
              df = df[variables]
              return df
docs: Get values
  
          Parameters
          ----------
          variables : list of strings, default None
                      list of variables names, if None return the whole table
          table : string, default None
                  name of the table hosting the variables
          lowercase : boolean, deflault True
                      put variables of the table into lowercase
          rename_ident :  boolean, deflault True
                          rename variables ident+yr (e.g. ident08) into ident
          Returns
          -------
          df : DataFrame, default None
               A DataFrame containing the variables