Troubles to calculate values from sensor data

Hey mates,

I am struggling with some basics here I believe.

I have created a template sensor in the configuration.yaml

         name: "Gasverbrauch m3"
         unit_of_measurement: m³
         device_class: gas
         state_class: total_increasing
         icon: mdi:meter-gas-outline
         unique_id: gasverbrauch_aqara
         state: { { 0.1 *  states('counter.gesamt_impulse_gas') | float(0) } }

But always following error occurs:

Error loading /config/configuration.yaml: invalid key: “{“0.1 * states(‘counter.gesamt_impulse_gas’) | float(0)”: None}” in “/config/configuration.yaml”,

Maybe someone can nudge me in the right direction
Thanks in advanced

Template Rule #1: Templates need to be surrounded by quote marks or preceded by a block-scalar indicator.

Also, { { is not the same as {{.