docs: def checkArgs(args):
      """Checks the arguments and options.
  
      :param args: an object containing the options of the program.
      :type args: argparse.Namespace
  
      :returns: ``True`` if everything was OK.
  
      If there is a problem with an option, an exception is raised using the
      :py:class:`ProgramError` class, a message is printed to the
      :class:`sys.stderr` and the program exists with code 1.
  
      """
      # Check if we have the tped and the tfam files
      for fileName in [args.bfile + i for i in [".bed", ".bim", ".fam"]]:
          if not os.path.isfile(fileName):
              msg = "%(fileName)s: no such file" % locals()
              raise ProgramError(msg)
  
      # Ceck the number of markers on chromosome 23
      if args.nbChr23 < 0:
          msg = ("{}: number of markers on chr 23 must be "
                 "positive".format(args.nbChr23))
          raise ProgramError(msg)
  
      # If we ask for LRR and BAF, we need a directory
      if args.lrr_baf:
          if not os.path.isdir(args.lrr_baf_raw_dir):
              msg = "{}: no such directory".format(args.lrr_baf_raw_dir)
              raise ProgramError(msg)
          if args.lrr_baf_dpi < 10:
              msg = "{}: DPI too low".format(args.dpi)
              raise ProgramError(msg)
  
      return True