[Need Help] Set Context - AppleScript

Automation OmniFocus Automation
#1

Not sure what I’m doing wrong.
I need to set context, or set a new context using AppleScript.

Thanks for any help.

tell application "OmniFocus"
	tell front document
		tell content of document window 1
			set SelectedTasks to value of every selected tree
			if ((count of SelectedTasks) < 1) then
				display alert "You must first select an item to complete." as warning
				return
			end if
			repeat with anItem in SelectedTasks
				set context of anItem to "Waiting"
			end repeat
		end tell
	end tell
end tell
#2

The problem is this: context is a property of the task class. Its class is context.
So you need to store a reference to the context element in a variable first.
Tell me if you have any more doubts.

Code:

property context_name : "Waiting"

tell application "OmniFocus"
	tell front document
		-- GET CONTEXT
		set lst_contexts to every flattened context whose (name = context_name)
		tell content of document window 1
			set SelectedTasks to value of every selected tree
			if ((count of SelectedTasks) < 1) then
				display alert "You must first select an item to complete." as warning
				return
			end if
		end tell
		if (length of lst_contexts) > 0 then
			set the_context to (item 1 of lst_contexts)
		else
			-- CONTEXT NOT EXISTS; CREATE CONTEXT
			set the_context to (make new context with properties {name:context_name})
		end if
		repeat with anItem in SelectedTasks
			set context of anItem to the_context
		end repeat
	end tell
end tell