'Print the message object tree rooted at msg to the output file
specified when the Generator instance was created.
unixfrom is a flag that forces the printing of a Unix From_ delimiter
before the first object in the message tree.  If the original message
has no From_ delimiter, a `standard\' one is crafted.  By default, this
is False to inhibit the printing of any From_ delimiter.
Note that for subobjects, no From_ line is printed.'

def flatten(self, msg, unixfrom=False):

    if unixfrom:
        ufrom = msg.get_unixfrom()
        if (not ufrom):
            ufrom = ('From    nobody    ' + time.ctime(time.time()))
        print >>self._fp, ufrom
    self._write(msg)
