Nothing seems to be using this module.

And it's written in the old ansible module style.

playbooks/library/vpc_lookup

-#!/usr/bin/python
-# This file is part of Ansible
-#
-# Ansible is free software: you can redistribute it and/or modify
-# it under the terms of the GNU General Public License as published by
-# the Free Software Foundation, either version 3 of the License, or
-# (at your option) any later version.
-#
-# Ansible is distributed in the hope that it will be useful,
-# but WITHOUT ANY WARRANTY; without even the implied warranty of
-# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-# GNU General Public License for more details.
-#
-# You should have received a copy of the GNU General Public License
-# along with Ansible.  If not, see <http://www.gnu.org/licenses/>.
-
-DOCUMENTATION = '''
----
-module: vpc_lookup
-short_description: returns a list of subnet Ids using tags as criteria
-description:
-     - Returns a list of subnet Ids for a given set of tags that identify one or more VPCs
-version_added: "1.5"
-options:
-  region:
-    description:
-      - The AWS region to use.  Must be specified if ec2_url
-        is not used.  If not specified then the value of the
-        EC2_REGION environment variable, if any, is used.
-    required: false
-    default: null
-    aliases: [ 'aws_region', 'ec2_region' ]
-  aws_secret_key:
-    description:
-      - AWS secret key. If not set then the value of
-        the AWS_SECRET_KEY environment variable is used.
-    required: false
-    default: null
-    aliases: [ 'ec2_secret_key', 'secret_key' ]
-  aws_access_key:
-    description:
-      - AWS access key. If not set then the value of the
-        AWS_ACCESS_KEY environment variable is used.
-    required: false
-    default: null
-    aliases: [ 'ec2_access_key', 'access_key' ]
-  tags:
-    desription:
-      - tags to lookup
-    required: false
-    default: null
-    type: dict
-    aliases: []
-
-requirements: [ "boto" ]
-author: John Jarvis
-'''
-
-EXAMPLES = '''
-# Note: None of these examples set aws_access_key, aws_secret_key, or region.
-# It is assumed that their matching environment variables are set.
-
-# Return all instances that match the tag "Name: foo"
-- local_action:
-    module: vpc_lookup
-    tags:
-        Name: foo
-'''
-
-import sys
-
-AWS_REGIONS = ['ap-northeast-1',
-               'ap-southeast-1',
-               'ap-southeast-2',
-               'eu-west-1',
-               'sa-east-1',
-               'us-east-1',
-               'us-west-1',
-               'us-west-2']
-
-try:
-    from boto.vpc import VPCConnection
-    from boto.vpc import connect_to_region
-except ImportError:
-    print "failed=True msg='boto required for this module'"
-    sys.exit(1)
-
-
-def main():
-
-    module=AnsibleModule(
-        argument_spec=dict(
-            region=dict(choices=AWS_REGIONS),
-            aws_secret_key=dict(aliases=['ec2_secret_key', 'secret_key'],
-                                no_log=True),
-            aws_access_key=dict(aliases=['ec2_access_key', 'access_key']),
-            tags=dict(default=None, type='dict'),
-        )
-    )
-
-    tags = module.params.get('tags')
-    aws_secret_key = module.params.get('aws_secret_key')
-    aws_access_key = module.params.get('aws_access_key')
-    region = module.params.get('region')
-
-    # If we have a region specified, connect to its endpoint.
-    if region:
-        try:
-            vpc = connect_to_region(region, aws_access_key_id=aws_access_key,
-                                    aws_secret_access_key=aws_secret_key)
-        except boto.exception.NoAuthHandlerFound, e:
-            module.fail_json(msg=str(e))
-    else:
-        module.fail_json(msg="region must be specified")
-    vpc_conn = VPCConnection()
-    subnet_ids = []
-    for subnet in vpc_conn.get_all_subnets(filters={'tag:' + tag: value
-                                      for tag, value in tags.iteritems()}):
-        subnet_ids.append(subnet.id)
-    vpc_ids = []
-    for vpc in vpc.get_all_vpcs(filters={'tag:' + tag: value
-                                      for tag, value in tags.iteritems()}):
-        vpc_ids.append(vpc.id)
-
-    module.exit_json(changed=False, subnet_ids=subnet_ids, vpc_ids=vpc_ids)
-
-
-# this is magic, see lib/ansible/module_common.py
-#<<INCLUDE_ANSIBLE_MODULE_COMMON>>
-
-main()