Unable to click checkbox of System Preferences by AppleScript, although it doesn't show errors - macos

Question

Errors
I had written the code below, and it seems to work until it select the row.
However, click checkbox doesn't work even though it doesn't give any errors.
tell application "System Preferences"
activate
reveal anchor "shortcutsTab" of pane id "com.apple.preference.keyboard"
end tell
tell application "System Events"
tell application process "System Preferences"
repeat while not (window 1 exists)
end repeat
tell window 1
repeat while not (rows of table 1 of scroll area 1 of splitter group 1 of tab group 1 exists)
end repeat
repeat with current_row in (rows of table 1 of scroll area 1 of splitter group 1 of tab group 1)
if value of static text 1 of current_row is equal to "Input Sources" then
select current_row
exit repeat
end if
end repeat
repeat while not (rows of outline 1 of scroll area 2 of splitter group 1 of tab group 1 exists)
end repeat
repeat with current_row in rows of outline 1 of scroll area 2 of splitter group 1 of tab group 1
if name of UI element 2 of current_row is equal to "Select next source in input menu" then
select current_row
click checkbox of current_row
exit repeat
end if
end repeat
end tell
end tell
end tell
What I have tried
I wrote below alternatively, but they all not work.
set value of checkbox of selected_row
set checkbox of selected_row to true
References
I searched many articles, but it doesn't solve.
How to click a checkbox of a drop-down tab in System Preferences
http://hints.macworld.com/article.php?story=20040317131326880
Any help is appreciated.

Answer 1

Change:
click checkbox of current_row
To:
click checkbox of UI element 1 of current_row
Tested your script on macOS Mojave, making the change shown above, and it worked as desired.