   # than {::onDidChange} in that it will immediately call your callback with the
   # current value of the config entry.
   #
+  # ### Examples
+  #
+  # You might want to be notified when the themes change. We'll watch
+  # `core.themes` for changes
+  #
+  # ```coffee
+  # atom.config.observe 'core.themes', (value) ->
+  #   # do stuff with value
+  # ```
+  #
+  # * `scopeDescriptor` (optional) {Array} of {String}s. See {::get} for examples
   # * `keyPath` {String} name of the key to observe
   # * `callback` {Function} to call when the value of the key changes.
   #   * `value` the new value of the key

  # Essential: Add a listener for changes to a given key path. If `keyPath` is
  # not specified, your callback will be called on changes to any key.
  #
  # * `keyPath` (optional) {String} name of the key to observe
  # * `callback` {Function} to call when the value of the key changes.
  #   * `event` {Object}
  #     * `newValue` the new value of the key

  #
  # This value is stored in Atom's internal configuration file.
  #
  # ### Examples
  #
  # You might want to change the themes programmatically:
  #
  # ```coffee
  # atom.config.set('core.themes', ['atom-light-ui', 'atom-light-syntax'])
  # ```
  #
  # You can also set scoped settings. For example, you might want change the
  # `editor.tabLength` only for ruby files.
  #
  # ```coffee
  # atom.config.get('editor.tabLength') # => 4
  # atom.config.get(['source.ruby'], 'editor.tabLength') # => 4
  # atom.config.get(['source.js'], 'editor.tabLength') # => 4
  #
  # # Set ruby to 2
  # atom.config.set('source.ruby', 'editor.tabLength', 2) # => true
  #
  # # Notice it's only set to 2 in the case of ruby
  # atom.config.get('editor.tabLength') # => 4
  # atom.config.get(['source.ruby'], 'editor.tabLength') # => 2
  # atom.config.get(['source.js'], 'editor.tabLength') # => 4
  # ```
  #
  # * `scope` (optional) {String}. eg. '.source.ruby'
  # * `keyPath` The {String} name of the key.
  # * `value` The value of the setting. Passing `undefined` will revert the
  #   setting to the default value.
