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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 _prepare_quote(quote, author, max_len=78):
 """This function processes a quote and returns a string that is ready to be used in the fancy prompt. """

    quote = quote.split(' ')
    max_len -= 6
    lines = []
    cur_line = []

    def _len(line):
        return sum(len(elt) for elt in line) + len(line) - 1
    while quote:
        if not cur_line or (_len(cur_line) + len(quote[0]) - 1 <= max_len):
            cur_line.append(quote.pop(0))
            continue
        lines.append('   | %s' % ' '.join(cur_line))
        cur_line = []
    if cur_line:
        lines.append('   | %s' % ' '.join(cur_line))
        cur_line = []
    lines.append('   | %s-- %s' % (" " * (max_len - len(author) - 5), author))
    return lines