Template Sensor Access Entity_id Variable

Feature Requests
1

Gday All,

I am building a package for estimating power draw on all my devices.

One thing that would really help this, and i am sure many other template sensors, is if i had access to the variables passed in the entity_id.

Given that a lot of the time we want the sensor to update based on the entity_id anyway, being able to access it will reduce potential errors, as well as clean up a lot of code.
e.g. how awesome would it be to be able to use a quick sensor like this to add the values of a bunch of sensors.

sensor:
    - platform: template
        sensors:
          my_summing_sensor:
            friendly_name: "Sum Entities"
            entity_id:
              - sensor.sensor_one
              - sensor.sensor_two
              - sensor.sensor_three
            value_template: >-
              {{ expand('entity_id') | map(attribute='state') | map('float') | sum }}

Or if you could run a loop through a bunch of entities in the entity_id list and do something?

Cheers!