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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 fa2s2b(fastas):
 """ convert fastas to s2b dictionary """

    s2b = {}
    for fa in fastas:
        for seq in parse_fasta(fa):
            s = seq[0].split('>', 1)[1].split()[0]
            s2b[s] = fa.rsplit('/', 1)[-1].rsplit('.', 1)[0]
    return s2b