não é mais usado essa forma de assinatura

ass_xml.py

@@ -1,16 +0,0 @@
-from lxml import etree
-import signxml
-from signxml import xmldsig
-
-cert = open("cert.pem").read()
-key = open("key.pem", "rb").read()
-
-root = etree.parse('texte.xml').getroot()
-signer = xmldsig(root, digest_algorithm="sha1")
-signer.sign(method=signxml.methods.enveloped, key=key, cert=cert,
-            algorithm="rsa-sha1", c14n_algorithm='http://www.w3.org/TR/2001/REC-xml-c14n-20010315',
-            reference_uri='#NFe41150715380524000122651010000000271333611649')
-#verified_data = signer.verify(require_x509=True, ca_pem_file="cert.pem")
-e = etree.tostring(signer.data)
-open("testesig.xml", "wb").write(e)
-