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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 create_temporary_ca_path(anchor_list, folder):
 """ Create a CA path folder as defined in OpenSSL terminology, by storing all certificates in 'anchor_list' list in PEM format under provided 'folder' and then creating the associated links using the hash as usually done by c_rehash. Note that you can also include CRL in 'anchor_list'. In that case, they will also be stored under 'folder' and associated links will be created. In folder, the files are created with names of the form if it does not already exist, but that's all. The number of certificates written to folder is returned on success, None on error. """

    # We should probably avoid writing duplicate anchors and also
    # check if they are all certs.
    try:
        if not os.path.isdir(folder):
            os.makedirs(folder)
    except:
        return None
    
    l = len(anchor_list)
    if l == 0:
        return None
    fmtstr = "%%0%sd.pem" % math.ceil(math.log(l, 10))
    i = 0
    try:
        for a in anchor_list:
            fname = os.path.join(folder, fmtstr % i)
            f = open(fname, "w")
            s = a.output(fmt="PEM")
            f.write(s)
            f.close()
            i += 1
    except:
        return None

    r,w,e=popen3(["c_rehash", folder])
    r.close(); w.close(); e.close()

    return l