code: def _frequency_generated_trips_rows(self, gtfs_soure_path, return_df_freq=False):
          
          df_freq = source_csv_to_pandas(gtfs_soure_path, 'frequencies')
          df_trips = source_csv_to_pandas(gtfs_soure_path, "trips")
          df_freq['n_trips'] = df_freq.apply(lambda row: len(range(str_time_to_day_seconds(row['start_time']),
                                                                   str_time_to_day_seconds(row['end_time']),
                                                                   row['headway_secs'])), axis=1)
          df_trips_freq = pd.merge(df_freq, df_trips, how='outer', on='trip_id')
          n_freq_generated_trips = int(df_trips_freq['n_trips'].fillna(1).sum(axis=0))
          if return_df_freq:
              return df_trips_freq
          else:
              return n_freq_generated_trips
docs: This function calculates the equivalent rowcounts for trips when
          taking into account the generated rows in the gtfs object
          Parameters
          ----------
          gtfs_soure_path: path to the source file
          param txt: txt file in question
          :return: sum of all trips