code: def main(argv: Optional[List[str]] = None) -> None:
      """
      Handle command line arguments and gets things started.
  
      Parameters
      ----------
      argv : Optional[List[str]], default=None
          List of arguments, as if specified on the command-line.
          If ``None``, ``sys.argv[1:]`` is used instead.
      """
      # Get command line arguments
      parser = argparse.ArgumentParser(
          description="Generates learning curve plots from the learning curve "
          "TSV file.",
          formatter_class=argparse.ArgumentDefaultsHelpFormatter,
          conflict_handler="resolve",
      )
      parser.add_argument(
          "tsv_file", help="Learning curve TSV output file."
      )
      parser.add_argument(
          "output_dir",
          help="Directory to store the learning curve plots.",
      )
      parser.add_argument(
          "--version",
          action="version",
          version=f"%(prog)s {__version__}",
      )
      args = parser.parse_args(argv)
  
      # Make warnings from built-in warnings module get formatted more nicely
      logging.captureWarnings(True)
      logging.basicConfig(
          format="%(asctime)s - %(name)s - %(levelname)s - "
          "%(message)s"
      )
  
      # convert to Path objects
      tsv_file = Path(args.tsv_file)
      output_dir = Path(args.output_dir)
  
      # make sure that the input TSV file that's being passed exists
      if not tsv_file.exists():
          logging.error(
              f"Error: the given file {args.tsv_file} does not "
              "exist."
          )
          sys.exit(1)
  
      # create the output directory if it doesn't already exist
      if not output_dir.exists():
          output_dir.mkdir(parents=True)
  
      # get the experiment name from the learning curve TSV file
      # output_file_name = experiment_name + '_summary.tsv'
      experiment_name = tsv_file.name.rstrip("_summary.tsv")
      logging.info("Generating learning curve(s)")
      generate_learning_curve_plots(
          experiment_name, args.output_dir, args.tsv_file
      )
  
file_path: skll/skll/utils/commandline/plot_learning_curves.py
imports: import argparse
  import logging
  import sys
  from pathlib import Path
  from typing import List, Optional
  from skll.experiments import generate_learning_curve_plots
  from skll.version import __version__
label_desc: Use image node_id 1 for calling a global function with example usage: main(argv) without return types