code: def delete(name=None, group=None, release=None, except_release=None,
      dryrun=1, verbose=1):
      
  
      verbose = int(verbose)
  
      if env.vm_type == EC2:
          conn = get_ec2_connection()
  
          instances = list_instances(
              name=name,
              group=group,
              release=release,
              except_release=except_release,
          )
  
          for instance_name, instance_data in instances.items():
              public_dns_name = instance_data['public_dns_name']
              print('\nDeleting %s (%s)...' \
                  % (instance_name, instance_data['id']))
              if not get_dryrun():
                  conn.terminate_instances(instance_ids=[instance_data['id']])
  
              # Clear host key on localhost.
              known_hosts = os.path.expanduser('~/.ssh/known_hosts')
              cmd = 'ssh-keygen -f "%s" -R %s' % (known_hosts, public_dns_name)
              local_or_dryrun(cmd)
  
      else:
          raise NotImplementedError
docs: Permanently erase one or more VM instances from existence.