code: def process_symbol(
      symbol, fromYear, toYear, missingDataVerifierClass
  ):
      logger.info(
          "Processing %s from %d to %d" % (symbol, fromYear, toYear)
      )
  
      filesFound = 0
      # Load the bars from the CSV files.
      feed = yahoofeed.Feed(maxLen=1000000)
      feed.sanitizeBars(True)
      for year in range(fromYear, toYear + 1):
          fileName = get_csv_filename(symbol, year)
          if os.path.exists(fileName):
              filesFound += 1
              feed.addBarsFromCSV(symbol, fileName)
  
      if filesFound > 0:
          # Process all items.
          for dateTime, bars in feed:
              pass
  
          missingDataVerifier = missingDataVerifierClass(feed[symbol])
          missingDataVerifier.run()
      else:
          logger.error("No files found")
  
imports: import sys
  import os
  import datetime
  import symbolsxml
  import merval_calendar
  import pyalgotrade.logger
  from pyalgotrade.barfeed import yahoofeed
label_desc: Use image node_id 2 for calling a global function with example usage: process_symbol(symbol, fromYear, toYear, missingDataVerifierClass) without return types