def ingredients(self, value):
for node in self.xml.xpath('./ingredient'):
node.getparent().remove(node)
for item in value:
self.xml.append(
E.ingredient(
code=item.code,
amount=item.amount if hasattr(item, 'amount') else '',
unit=item.unit if hasattr(item, 'unit') else '',
details=item.details if hasattr(item, 'details') else ''))
