code: def main():
      barFeed = barfeed.CSVTradeFeed()
      barFeed.addBarsFromCSV(
          "bitstampUSD.csv", fromDateTime=datetime.datetime(2014, 1, 1)
      )
      resample.resample_to_csv(
          barFeed, bar.Frequency.MINUTE * 30, "30min-bitstampUSD.csv"
      )
  
imports: from pyalgotrade.bitcoincharts import barfeed
  from pyalgotrade.tools import resample
  from pyalgotrade import bar
  import datetime
label_desc: Use image node_id 1 for calling a global function with example usage: main() without return types