You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: untexlabel.m
    path of file: ./repos/tracacode/1911-COAWST/script/mfiles/rutgers/utility
    
    the code of the file until where you have to start completion: function newstr = untexlabel(str)

% newstr = untexlabel(str)
% 
% Produces a TeX format from a character string. It Builds a string
% which used with a TeX inter
    
function newstr = untexstring(str)
%==========================================================================

% This is for a single string line

newstr = '';

if ~isempty(str),
  index1 = find(str=='^');        % get '^' index
  index2 = find(str=='_');        % get '_' index
  index3 = find(str=='\');        % get '\' index

  index_end