code: def enrich(self, columns):
          
  
          for column in columns:
              if column not in self.data.columns:
                  return self.data
  
          self.data = pandas.merge(self.data, self.uuids_df, how='left', on=columns)
          self.data = self.data.fillna("notavailable")
  
          return self.data
docs: Merges the original dataframe with corresponding entity uuids based
          on the given columns. Also merges other additional information
          associated to uuids provided in the uuids dataframe, if any.
  
          :param columns: columns to match for merging
          :type column: string array
  
          :return: original dataframe with at least one new column:
           * uuid: identity unique identifier
          :rtype: pandas.DataFrame