Adds a maintenance sub type. All maintenanceSubTypeInfo keys are required unless otherwise stated

---
### Parameters
**maintenanceSubTypeInfo** `Dictionary`<br />
<table class='dictionaryKeyTable'>
	<tbody>
 	<tr><td> - enabled</td><td>Boolean</td><td>Not required. Set to True if not passed</td></tr>	
 	<tr><td> - maintenanceSubTypeName</td><td>String</td><td>Name of sub type</td></tr>	
 	<tr><td> - maintenanceTypeId</td><td>Integer</td><td></td></tr>	
	</tbody>
</table>

**userId** `Integer`:Id of the user executing the function<br />

---
### Returns
**maintenanceSubTypeId** `Integer`<br />
**message** `String` None if success<br />

---
### Example
```python
# Add a new maintenance sub type under an existing parent maintenance type
maintenanceSubTypeInfo = {
							"enabled": True,
							"maintenanceSubTypeName": "Bearing Replacement",
							"maintenanceTypeId": 4  # id of the "Mechanical" MaintenanceType
						}
userId = system.kanoa.security.getIDPUserId({'userName': 'SYSTEM'})
maintenanceSubTypeId, message = system.kanoa.cmms.addMaintenanceSubType(maintenanceSubTypeInfo, userId)
print maintenanceSubTypeId, message
```