code: def read_same_samples_file(filename, out_prefix):
      
      # The same samples
      same_samples = []
  
      # Creating the extraction files
      gold_file = None
      try:
          gold_file = open(out_prefix + ".gold_samples2keep", 'w')
      except IOError:
          msg = "{}: can't create file".format(out_prefix + ".gold_samples2keep")
          raise ProgramError(msg)
  
      source_file = None
      try:
          source_file = open(out_prefix + ".source_panel_samples2keep", 'w')
      except IOError:
          msg = ("{}: can't create "
                 "file".format(out_prefix + ".source_panel_samples2keep"))
          raise ProgramError(msg)
  
      with open(filename, 'r') as input_file:
          for line in input_file:
              row = line.rstrip("\r\n").split("\t")
  
              # Getting the samples
              gold_sample = tuple(row[:2])
              source_sample = tuple(row[2:])
              same_samples.append((gold_sample, source_sample))
  
              # Printing files
              print >>gold_file, "\t".join(gold_sample)
              print >>source_file, "\t".join(source_sample)
  
      # Closing the files
      gold_file.close()
      source_file.close()
  
      return same_samples
docs: Reads a file containing same samples.