def update_author(xml):
"Executes xml, creates author or updates inf about it."
entity_id = get_id(xml)
if entity_id is None:
# Create new author
author = Author()
else:
# Modify existing author
author = Author.objects.get(id=entity_id)
full_name = get_tag_text(xml, 'full_name')
if full_name:
author.name = full_name
if not author.name:
raise IntegrityError("'full_name' can't be empty")
try:
credit_str = get_tag_text(xml, 'credit')
if credit_str:
credit = int(credit_str)
author.credit = credit
except ValueError, ex:
raise InputDataServerException(ex)
