'Verify the signature on the contents of the string \'data\'
>>> gpg = GPG(gnupghome="keys")
>>> input = gpg.gen_key_input(Passphrase=\'foo\')
>>> key = gpg.gen_key(input)
>>> assert key
>>> sig = gpg.sign(\'hello\',keyid=key.fingerprint,passphrase=\'bar\')
>>> assert not sig
>>> sig = gpg.sign(\'hello\',keyid=key.fingerprint,passphrase=\'foo\')
>>> assert sig
>>> verify = gpg.verify(sig.data)
>>> assert verify'

def verify(self, data):

    f = _make_binary_stream(data, self.encoding)
    result = self.verify_file(f)
    f.close()
    return result
