This operation is used to get the latest switch status on an equipment protection group.

For a retrieval of a revertive M:N group, N ESwitchData objects are returned (one for each
worker equipment instance).
For a retrieval of a non-revertive M:N group, N ESwitchData objects are returned (one for
each active equipment instance).

Operation Exceptions:
1. NOT_IMPLEMENTED - Raised when the EMS does not support this operation.
2. INTERNAL_ERROR - Raised in case of non-specific EMS internal failure.
3. NE_COMM_LOSS - Raised when communication to managed element is lost.
