code: def ngram2mgram(input_file, output_file, n, m, words=False, ascii_idngram=False):
      
      cmd = ['ngram2mgram', '-n', n,
                            '-m', m]
  
      if words and ascii_idngram:
          raise ConversionError("Parameters 'words' and 'ascii_idngram' cannot both be True")
  
      if words:
          cmd.append('-words')
      elif ascii_idngram:
          cmd.append('-ascii')
      else:
          cmd.append('-binary')
  
      # Ensure that every parameter is of type 'str'
      cmd = [str(x) for x in cmd]
  
      with open(input_file,'r') as input_f:
          with open(output_file,'w+') as output_f:
              with  output_to_debuglogger() as err_f:
                  exitcode = subprocess.call(cmd, stdin=input_f, 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 either a word n-gram file, or an id n-gram file and outputs a file of the same type where m < n.