Check if tab exist

tell application "Google Chrome"
    repeat with w in windows
        set i to 1
        repeat with t in tabs of w
            if URL of t starts with "https://mail.google" then
                set active tab index of w to i
                set index of w to 1
                return
            end if
            set i to i + 1
        end repeat
    end repeat
    open location "https://mail.google.com/mail/u/0/#inbox"
end tell