'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 vpc_id: str
:param vpc_id: The ID of the instance to unlink from the VPC.
: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_link_vpc(self, vpc_id, instance_id, dry_run=False):

    params = {'VpcId': vpc_id, 'InstanceId': instance_id}
    if dry_run:
        params['DryRun'] = 'true'
    return self.get_status('DetachClassicLinkVpc', params)
