@property<EOL><INDENT>def _parent_id(self):<DEDENT>
if hasattr(self, '<STR_LIT>'):<EOL><INDENT>return self.course_id<EOL><DEDENT>elif hasattr(self, '<STR_LIT>'):<EOL><INDENT>return self.group_id<EOL><DEDENT>elif hasattr(self, '<STR_LIT>'):<EOL><INDENT>return self.account_id<EOL><DEDENT>elif hasattr(self, '<STR_LIT>'):<EOL><INDENT>return self.user_id<EOL><DEDENT>else:<EOL><INDENT>raise ValueError(<EOL>"<STR_LIT>")<EOL><DEDENT>
Return the id of the account, course, group, or user that spawned
this content migration.

:rtype: int