code: def start(self):
      paths = self.kernel_spec_manager.find_kernel_specs()
      specs = self.kernel_spec_manager.get_all_specs()
      if not self.json_output:
          if not specs:
              print("No kernels available")
              return
          # pad to width of longest kernel name
          name_len = len(sorted(paths, key=lambda name: len(name))[-1])
  
          def path_key(item):
              """sort key function for Jupyter path priority"""
              path = item[1]
              for idx, prefix in enumerate(self.jupyter_path):
                  if path.startswith(prefix):
                      return (idx, path)
              # not in jupyter path, artificially added to the front
              return (-1, path)
  
          print("Available kernels:")
          for kernelname, path in sorted(paths.items(), key=path_key):
              print("  %s    %s" % (kernelname.ljust(name_len), path))
      else:
          print(json.dumps({"kernelspecs": specs}, indent=2))
  
imports: from __future__ import print_function
  import errno
  import os.path
  import sys
  import json
  from traitlets.config.application import Application
  from jupyter_core.application import JupyterApp, base_flags, base_aliases
  from traitlets import Instance, Dict, Unicode, Bool, List
  from .None import __version__
  from .kernelspec import KernelSpecManager
label_desc: Use image node_id 2 for calling the ListKernelSpecs obj's underlying member method code with example usage: obj.start() and returns: unknown,  path, idx,  path