patches/pylint: teach astroid about xmlsec modules

python xmlsec's xmlsec.so contains multiple level module in the same
.so (xmlsec, xmlsec.template etc) and this seem to cause problems to
astroid, trying to lint a module containing:

  import xmlsec
  xmlsec.template.encrypted_data_create('...')

cause an error:

   File "develop-eggs/astroid-1.3.8+slapospatched001-py2.7.egg/astroid/raw_building.py", line 360, in _set_proxied
      return _CONST_PROXY[const.value.__class__]
  KeyError: <type 'module'>

and unlike similar error happening with ffi's module from cryptography,
retrying does not help.

product/ERP5Type/patches/pylint.py

@@ -381,6 +381,16 @@ _register_module_extender_from_live_module(
   'cryptography.hazmat.bindings._openssl',
   cryptography.hazmat.bindings._openssl)
 
+
+try:
+  import xmlsec
+except ImportError:
+  pass
+else:
+  _register_module_extender_from_live_module('xmlsec', xmlsec)
+  _register_module_extender_from_live_module('xmlsec.tree', xmlsec.tree)
+  _register_module_extender_from_live_module('xmlsec.template', xmlsec.template)
+
 # Properly search for namespace packages: original astroid (as of 1.3.8) only
 # checks at top-level and it doesn't work for Shared.DC.ZRDB (defined in
 # Products.ZSQLMethods; Shared and Shared.DC being a namespace package defined

product/ERP5Type/tests/testDynamicClassGeneration.py

@@ -2306,6 +2306,18 @@ rsa.generate_private_key(
   key_size=2048,
 ).public_key()
 
+def xmlsec_decrypt():
+  # from https://xmlsec.readthedocs.io/en/stable/examples.html#decrypt
+  import xmlsec
+  manager = xmlsec.KeysManager()
+  key = xmlsec.Key.from_file('rsakey.pem', xmlsec.constants.KeyDataFormatPem)
+  manager.add_key(key)
+  enc_ctx = xmlsec.EncryptionContext(manager)
+  root = lxml.etree.parse("enc1-res.xml").getroot()
+  enc_data = xmlsec.tree.find_child(root, "EncryptedData", xmlsec.constants.EncNs)
+  decrypted = enc_ctx.decrypt(enc_data)
+  print(lxml.etree.tostring(decrypted))
+
 """ % (dict(namespace=namespace,
             reference1=imported_reference1,
             module2=imported_module2,