docs: def preprocess_input(userinput):
    """
    <Purpose>
      Preprocess the raw command line input string.
  
    <Arguments>
      The raw command line input string.  We assume it is pre-stripped.
  
    <Side Effects>
      The string will be processed by each module that has a defined preprocessor.
  
    <Exceptions>
      None
  
    <Returns>
      The preprocessed string.
    """
    for module in get_enabled_modules():
      # Not every module has a preprocessor...
      if 'input_preprocessor' in module_data[module]:
        userinput = module_data[module]['input_preprocessor'](userinput)
    return userinput