code: def validate_input_file_list(input_filepath_list):
      '''Input file list validation function. Checks that object is a list and
      contains valid filepaths that can be processed by SoX.
  
      Parameters
      ----------
      input_filepath_list : list
          A list of filepaths.
  
      '''
      if not isinstance(input_filepath_list, list):
          raise TypeError("input_filepath_list must be a list.")
      elif len(input_filepath_list) < 2:
          raise ValueError("input_filepath_list must have at least 2 files.")
  
      for input_filepath in input_filepath_list:
          validate_input_file(input_filepathf validate_input_file_list(input_filepath_list):
      '''Input file list validation function. Checks that object is a list and
      contains valid filepaths that can be processed by SoX.
  
      Parameters
      ----------
      input_filepath_list : list
          A list of filepaths.
  
      '''
      if not isinstance(input_filepath_list, list):
          raise TypeError("input_filepath_list must be a list.")
      elif len(input_filepath_list) < 2:
          raise ValueError("input_filepath_list must have at least 2 files.")
  
      for input_filepath in input_filepath_list:
          validate_input_file(input_filepath)
docs: Input file list validation function. Checks that object is a list and
      contains valid filepaths that can be processed by SoX.
  
      Parameters
      ----------
      input_filepath_list : list
          A list of filepaths.