<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def add(self, resource, provider_uri_or_id, timeout=-1):
 """ Adds a Device Manager under the specified provider. Args: resource (dict):
 Object to add. provider_uri_or_id: ID or URI of provider. timeout: Timeout in seconds. Wait for task completion by default. The timeout does not abort the operation in OneView, just stop waiting for its completion. Returns: dict: Added SAN Manager. """

        uri = self._provider_client.build_uri(provider_uri_or_id) + "/device-managers"
        return self._client.create(resource=resource, uri=uri, timeout=timeout)