Fix error XML model import

model/errorCCE.py

@@ -16,6 +16,7 @@ from sqlalchemy.ext.associationproxy import association_proxy
 from sqlalchemy.orm.exc import NoResultFound
 
 from model.core import Base, Core
+from model.xml import XML
 
 from model.author import Author
 from model.publisher import Publisher

model/xml.py

@@ -13,7 +13,6 @@ from sqlalchemy import (
 )
 
 from model.core import Base, Core
-from model.errorCCE import ErrorCCE
 
 @compiles(String, 'postgresql')
 def compile_xml(type_, compiler, **kw):