How to specify which module a matching interface name call goes to

[Zimzarina]

Hi, in an addon I am trying to call a built in blizzard code function specifically AutoComplete_Update. However calling it directly with simply AutoComplete_Update(etc does not get the correct one. There are two such matching functions in the blizzard code (details below). How do I force lua to call the specific one I want (The in AutoComplete.lua is the one I wish to use.)? Thanks!
_retail_\BlizzardInterfaceCode\Interface\FrameXML\AutoComplete.lua
Line 144: function AutoComplete_Update(parent, text, cursorPosition)
vs
_retail_\BlizzardInterfaceCode\Interface\FrameXML\ChatFrame.lua
Line 4893: AutoComplete_Update(self, target, self:GetUTF8CursorPosition() - strlenutf8(command) - 1);
Line 4922: AutoComplete_Update(self, target, utf8Position - strlenutf8(command) - strlen(whitespace))