def add_from_existing(self, resource, timeout=-1):
        """
        Adds a volume that already exists in the Storage system

        Args:
            resource (dict):
                Object to create.
            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 resource.
        """
        uri = self.URI + "/from-existing"
        return self._client.create(resource, uri=uri, timeout=timeout)
Adds a volume that already exists in the Storage system

        Args:
            resource (dict):
                Object to create.
            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 resource.