docs: def run_supernova_keyring(ctx, action, environment, parameter):
      """
      Sets or retrieves credentials stored in your system's keyring using the
      python-keyring module.
  
      Global credentials can be shared between multiple configuration sections:
  
      \b
          [prod]
          OS_PASSWORD=USE_KEYRING['sso_password']
          ...
  
      \b
          [staging]
          OS_PASSWORD=USE_KEYRING['my sso_password']
          ...
  
      You could retrieve or set the global credential using these commands:
  
      \b
          supernova -g global sso_password     <= get the credential
          supernova -s global sso_password     <= set the credential
  
      Local credentials are intended for use with only one configuration section:
  
      \b
          [prod]
          OS_PASSWORD=USE_KEYRING
          ...
  
      \b
          [staging]
          OS_PASSWORD=USE_KEYRING
          ...
  
      You could retrieve or set the local credential using these commands:
  
      \b
          supernova -g prod OS_PASSWORD     <= get the credential for prod
          supernova -s prod OS_PASSWORD     <= set the credential for prod
  
      \b
          supernova -g staging OS_PASSWORD  <= get the credential for staging
          supernova -s staging OS_PASSWORD  <= set the credential for staging
  
      Full documentation:
  
      \b
          http://supernova.readthedocs.org/en/latest/configuring/
  
      """
      if action == 'get_credential':
          result = credentials.get_user_password(env=environment,
                                                 param=parameter)
          if not result:
              click.echo("\nUnable to find a credential matching the data "
                         "provided.")
              ctx.exit(1)
          else:
              click.echo("\nFound credential for {0}: {1}".format(*result))
              ctx.exit()
  
      elif action == 'set_credential':
          msg = """
  Preparing to set a credential in the keyring for:
  
    - Environment  : {0}
    - Parameter    : {1}
  
  If this is correct, enter the corresponding credential to store in your keyring
  or press CTRL-C to abort""".format(environment, parameter)
          credential = click.prompt(text=msg, hide_input=True)
  
          result = credentials.set_user_password(environment=environment,
                                                 parameter=parameter,
                                                 password=credential)
  
          if result:
              click.echo("\nSuccessfully stored.")
              ctx.exit()
          else:
              click.echo("\nUnable to store your credential.")
              ctx.exit(1)
      else:
          click.secho("ERROR: must specify --get or --set", bold=True)
          click.echo(ctx.get_help())
          ctx.exit()