Binary Sensor Template IF with Operations

Hey All. If I try this in the templates bit of the ui I get the correct result:
{%- if as_timestamp(now()) - as_timestamp(states.binary_sensor.luke_motion.last_changed) < 10*60 -%} Occupied {%- else -%} Empty {%- endif -%}
But if I add it to my config I get ’ [homeassistant.components.binary_sensor.template] Could not render template Occupied, the state is unknown’
`
binary_sensor:

  • platform: template
    sensors:
    luke_occupancy:
    friendly_name: ‘Occupied’
    device_class: occupancy
    value_template: >
    {%- if as_timestamp(now()) - as_timestamp(states.binary_sensor.luke_motion.last_changed) < 10*60 -%}
    Occupied
    {%- else -%}
    Empty
    {%- endif -%}
    `
    Any ideas what I’m doing wrong?[details=Summary]This text will be hidden[/details]

Arghhh ignore me. It’s a binary sensor. Doh!