Something

import gpgmeimport sysimport StringIOsig = open(sys.argv[1], 'r')if len(sys.argv) > 2:    signed_text = open(sys.argv[2], 'r')    plaintext = Noneelse:    signed_text = None    plaintext = StringIO.StringIO()ctx = gpgme.Context()try:    sigs = ctx.verify(sig, signed_text, plaintext)except gpgme.GpgmeError, e:    print 'INVALID SIGNATURE - AWOOOOOOOOOGA'else:    thissig = sigs[0]    if thissig:        print thissig.fpr        if thissig.validity in (gpgme.VALIDITY_FULL,                            gpgme.VALIDITY_MARGINAL,                            gpgme.VALIDITY_ULTIMATE):            print 'trusted signature'        else:            print 'unsigned signature'