Shelly 3em to one

template
  - sensor:
    energy_totalvandvarmer1:
      friendly_name: 'Vandvarmer'
      value_template: "{{ (states('sensor.shellyem3_34945474b4ed_channel_a_energy')|float + states('sensor.shellyem3_34945474b4ed_channel_b_energy')|float + states('sensor.shellyem3_34945474b4ed_channel_c_energy')|float)|round(3) }}"
      unit_of_measurement: "kWh"
      device_class: energy