code: def insert_processing_option_group(parser):
      
      processing_group = parser.add_argument_group("Options for selecting the"
                                     " processing scheme in this program.")
      processing_group.add_argument("--processing-scheme",
                        help="The choice of processing scheme. "
                             "Choices are " + str(list(set(scheme_prefix.values()))) +
                             ". (optional for CPU scheme) The number of "
                             "execution threads "
                             "can be indicated by cpu:NUM_THREADS, "
                             "where NUM_THREADS "
                             "is an integer. The default is a single thread. "
                             "If the scheme is provided as cpu:env, the number "
                             "of threads can be provided by the PYCBC_NUM_THREADS "
                             "environment variable. If the environment variable "
                             "is not set, the number of threads matches the number "
                             "of logical cores. ",
                        default="cpu")
  
      processing_group.add_argument("--processing-device-id",
                        help="(optional) ID of GPU to use for accelerated "
                             "processing",
                        default=0, type=int)
docs: Adds the options used to choose a processing scheme. This should be used
      if your program supports the ability to select the processing scheme.
  
      Parameters
      ----------
      parser : object
          OptionParser instance