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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 andify(list_of_strings):
 """ Given a list of strings will join them with commas and a final "and" word. 'Apples, Oranges and Mangos' """

    result = ', '.join(list_of_strings)
    comma_index = result.rfind(',')
    if comma_index > -1: result = result[:comma_index] + ' and' + result[comma_index+1:]
    return result