'Sign a buffer via temp files.
Our signing tool can\'t sign a buffer, so we work around it using temporary
files.
Args:
in_buffer: data to sign
Returns:
signed data'

def SignBuffer(self, in_buffer):

    with tempfile.NamedTemporaryFile() as temp_in:
        temp_in.write(in_buffer)
        temp_in.seek(0)
        outfile = self.SignFile(temp_in.name)
        return open(outfile, 'rb').read()
