'Registers an Elastic IP address with a specified stack. An
address can be registered with only one stack at a time. If
the address is already registered, you must first deregister
it by calling DeregisterElasticIp. For more information, see
`Resource Management`_.
**Required Permissions**: To use this action, an IAM user must
have a Manage permissions level for the stack, or an attached
policy that explicitly grants permissions. For more
information on user permissions, see `Managing User
Permissions`_.
:type elastic_ip: string
:param elastic_ip: The Elastic IP address.
:type stack_id: string
:param stack_id: The stack ID.'

def register_elastic_ip(self, elastic_ip, stack_id):

    params = {'ElasticIp': elastic_ip, 'StackId': stack_id}
    return self.make_request(action='RegisterElasticIp', body=json.dumps(params))
