update sys.path and make sure the new items come first

Add `key` preference with `callback` function Whenever `key` is set the callback is called with the given `value` as paramete

Notify this observer when execution finishes

Another simple hack that helps with some packages: add all files in a package as completion options

Look at scopes which have been fully examined and report names in them which were imported but unused.

Clear all entries in global-name cache It might be a good idea to use this function before regenerating global names.

Clear the changed status of lines from start till end

Counts the number of basic changes a `Change` will make

Schedule an assignment handler to be called just after deferred function handlers.

Schedule a function handler to be called just before completion. This is used for handling function bodies, which must be deferred

Perform the change and add it to the `self.undo_list` Note that uninteresting changes (changes to ignored files) will not be appended

Find the primary and pyname at offset