def _fold(header):

    i = header.rfind("\r\n ")
    if i == -1:
        pre = ""
    else:
        i += 3
        pre = header[:i]
        header = header[i:]
    while len(header) > 72:
        i = header[:72].rfind(" ")
        if i == -1:
            i = j = 72
        else:
            j = i + 1
        pre += header[:i] + "\r\n "
        header = header[j:]
    return pre + header
Assert that two lists of L{Project}s are equal.
dataset/ETHPy150Open mailgun/flanker/flanker/dkim.py/_fold--crossover with--dataset/ETHPy150Open twisted/twisted/twisted/python/test/test_release.py/ProjectTests.assertProjectsEqual