docs: async function () {
  
          // while the array of all exchanges is not empty
          while (exchanges.length > 0) {
  
              // pop one exchange from the array
              const exchange = exchanges.pop ()
  
              // check if it has the necessary method implemented
              if (exchange.has['fetchTickers']) {
  
                  // try to do "the work" and handle errors if any
                  try {
  
                      // fetch the response for all tickers from the exchange
                      const tickers = await exchange.fetchTickers ()
  
                      // make a filename from exchange id
                      const filename = exchange.id + '.json'
  
                      // save the response to a file
                      fs.writeFileSync (filename, JSON.stringify ({ tickers }));
  
                      // print out a message on success
                      log.green (exchange.id, 'tickers saved to', filename)
  
                  } catch (e) {
  
                      // in case of error - print it out and ignore it further
                      log.red (e.constructor.name, e.message)
                  }
  
              } else {
  
                  log.red (exchange.id, "has['fetchTickers'] = false");
              }
          }
      }