If I have a device handler with the below capabilites and attributes. How do I reference them in both the preferences and subscriptions and the individual values?
capability "Energy Meter"
capability "Power Meter"
capability "Configuration"
capability "Sensor"
capability “Refresh”
//capability “Polling”
attribute "E_L1_L2", "number"
attribute "E_L1", "number"
attribute "E_L2", "number"