code: def validate_input_file(input_filepath):
      '''Input file validation function. Checks that file exists and can be
      processed by SoX.
  
      Parameters
      ----------
      input_filepath : str
          The input filepath.
  
      '''
      if not os.path.exists(input_filepath):
          raise IOError(
              "input_filepath {} does not exist.".format(input_filepath)
          )
      ext = file_extension(input_filepath)
      if ext not in VALID_FORMATS:
          logger.info("Valid formats: %s", " ".join(VALID_FORMATS))
          logger.warning(
              "This install of SoX cannot process .{} files.".format(ext)
          f validate_input_file(input_filepath):
      '''Input file validation function. Checks that file exists and can be
      processed by SoX.
  
      Parameters
      ----------
      input_filepath : str
          The input filepath.
  
      '''
      if not os.path.exists(input_filepath):
          raise IOError(
              "input_filepath {} does not exist.".format(input_filepath)
          )
      ext = file_extension(input_filepath)
      if ext not in VALID_FORMATS:
          logger.info("Valid formats: %s", " ".join(VALID_FORMATS))
          logger.warning(
              "This install of SoX cannot process .{} files.".format(ext)
          )
docs: Input file validation function. Checks that file exists and can be
      processed by SoX.
  
      Parameters
      ----------
      input_filepath : str
          The input filepath.