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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def word_intersection( word_a, word_b ):
 """ return a list of tuples where word_a, word_b intersect """

    positions = []
    word_a_letters = get_letters( word_a )
    word_b_letters = get_letters( word_b )
    for idx,wa in enumerate(word_a_letters):
        for idy,wb in enumerate(word_b_letters):
            if ( wa == wb ):
                positions.append( (idx, idy) )
    return positions