def wulffmaker_index(miller_index):
    """
    Returns the string to be used for the Wulffmaker default index. 
    
    Arguments
    ---------
    miller_index: iterable
        Any iterable that holds the miller indices as a iteratable of length 3. 
        
    Returns
    -------
    str
        String to be copied to wulffmaker for the miller indices. 
    
    """
    index_string = "pickIndex[i_, j_] :=\n"
    index_string += "Which[\n"
    
    for idx,index in enumerate(miller_index):
        ## Mathematica indexing starts at 1
        idx += 1
        
        temp_string = "i=={},\n".format(idx)
        temp_string += "Which[j==1,{},j==2,{},j==3,{},True,1],\n".format(
                        index[0], index[1], index[2])
        
        index_string += temp_string
        
    index_string += "True,\n"
    index_string += "RandomInteger[{-3, 3}]]"
        
    return index_string