'Format additional fields as text'

def _show(self, prefix):

    s = (prefix + 'format:    ')
    if (self.format == NXPIF_NXM):
        s += 'NXM'
    elif (self.format == NXPIF_OPENFLOW10):
        s += 'OF1.0'
    else:
        s += str(self.format)
    return (s + '\n')
