def schema_validation_errors(self):
if self.xmlschema is not None:<EOL><INDENT>return self.xmlschema.error_log<EOL><DEDENT>else:<EOL><INDENT>raise Exception('<STR_LIT>')<EOL><DEDENT>
Retrieve any validation errors that occured during schema validation
done via :meth:`is_valid`.

:returns: a list of :class:`lxml.etree._LogEntry` instances
:raises: Exception if no XSD schema is defined for this XmlObject instance