code: def mergeidngram(output_file, input_files, n=3, ascii_input=False, ascii_output=False):
      
      cmd = ['mergeidngram']
      if n:
          cmd.extend(['-n', n])
      
      if ascii_input:
          cmd.append('-ascii_input')
      
      if ascii_output:
          cmd.append('-ascii_output')
  
      if len(input_file) > 1:
          raise MergeError("mergeidngram needs at least 1 input file")
  
      cmd.extend(input_files)
  
      # Ensure that every parameter is of type 'str'
      cmd = [str(x) for x in cmd]
  
      with open(output_file,'w+') as output_f:
          with  output_to_debuglogger() as err_f:
              exitcode = subprocess.call(cmd, stdout=output_f, stderr=err_f)
      
      logger = logging.getLogger(__name__)
      logger.debug("Command '%s' returned with exit code '%d'." % (' '.join(cmd), exitcode))
  
      if exitcode != 0:
          raise ConversionError("'%s' returned with non-zero exit status '%s'" % (cmd[0], exitcode))
docs: Takes a set of id n-gram files (in either binary (by default) or ASCII (if specified) format - note that they should all be in the same format, however) and outputs a merged id N-gram.
  
          Notes : This function can also be used to convert id n-gram files between ascii and binary formats.