'Unlinks a linked EC2-Classic instance from a VPC. After the instance
has been unlinked, the VPC security groups are no longer associated
with it. An instance is automatically unlinked from a VPC when
it\'s stopped.
:type intance_id: str
:param instance_is: The ID of the VPC to which the instance is linked.
:type dry_run: bool
:param dry_run: Set to True if the operation should not actually run.
:rtype: bool
:return: True if successful'

def detach_classic_instance(self, instance_id, dry_run=False):

    return self.connection.detach_classic_link_vpc(vpc_id=self.id, instance_id=instance_id, dry_run=dry_run)
