nodes: 0, module; 1, function_definition; 2, function_name:get_isolated_cpus; 3, parameters; 4, block; 5, expression_statement; 6, comment:# The cpu/isolated sysfs was added in Linux 4.2; 7, comment:# (commit 59f30abe94bff50636c8cad45207a01fdcb2ee49); 8, expression_statement; 9, expression_statement; 10, if_statement; 11, expression_statement; 12, if_statement; 13, return_statement; 14, comment:"""Get the list of isolated CPUs.
  
      Return a sorted list of CPU identifiers, or return None if no CPU is
      isolated.
      """; 15, assignment; 16, assignment; 17, identifier:isolated; 18, block; 19, assignment; 20, identifier:cmdline; 21, block; 22, None; 23, identifier:path; 24, call; 25, identifier:isolated; 26, call; 27, return_statement; 28, identifier:cmdline; 29, call; 30, expression_statement; 31, if_statement; 32, identifier:sysfs_path; 33, argument_list; 34, identifier:read_first_line; 35, argument_list; 36, call; 37, identifier:read_first_line; 38, argument_list; 39, assignment; 40, identifier:match; 41, block; 42, string; 43, identifier:path; 44, identifier:parse_cpu_list; 45, argument_list; 46, call; 47, identifier:match; 48, call; 49, expression_statement; 50, return_statement; 51, string_content:devices/system/cpu/isolated; 52, identifier:isolated; 53, identifier:proc_path; 54, argument_list; 55, attribute; 56, argument_list; 57, assignment; 58, call; 59, string; 60, identifier:re; 61, identifier:search; 62, string; 63, identifier:cmdline; 64, identifier:isolated; 65, call; 66, identifier:parse_cpu_list; 67, argument_list; 68, string_content:cmdline; 69, string_content:\bisolcpus=([^ ]+); 70, attribute; 71, argument_list; 72, identifier:isolated; 73, identifier:match; 74, identifier:group; 75, integer:1
code: def get_isolated_cpus():
      """Get the list of isolated CPUs.
  
      Return a sorted list of CPU identifiers, or return None if no CPU is
      isolated.
      """
      # The cpu/isolated sysfs was added in Linux 4.2
      # (commit 59f30abe94bff50636c8cad45207a01fdcb2ee49)
      path = sysfs_path('devices/system/cpu/isolated')
      isolated = read_first_line(path)
      if isolated:
          return parse_cpu_list(isolated)
  
      cmdline = read_first_line(proc_path('cmdline'))
      if cmdline:
          match = re.search(r'\bisolcpus=([^ ]+)', cmdline)
          if match:
              isolated = match.group(1)
              return parse_cpu_list(isolated)
  
      return None