How to guard this template during startup

Configuration
1

How can I guard this template in a markdown card, which apparently isn’t ready when it is called:

2021-05-17 14:07:56 ERROR (MainThread) [homeassistant.helpers.template] Template variable error: 'None' has no attribute 'split' when rendering '{% set alarm_color = state_attr('binary_sensor.meteoalarm_brabant','awareness_level').split(' ')[1].split(';')[0] %} ## <font color= {{alarm_color}}> {{state_attr('binary_sensor.meteoalarm_brabant','headline')}}</font>
<font color= {{alarm_color}}><ha-icon icon= {{states('sensor.meteoalarm_icon')}}></ha-icon></font>
<font color= {{alarm_color}}> **Severity:**</font> {{state_attr('binary_sensor.meteoalarm_brabant','severity')}}
<font color= {{alarm_color}}> **Type:**</font> {{state_attr('binary_sensor.meteoalarm_brabant', 'awareness_type')}}
<font color= {{alarm_color}}> **Description:**</font>
{{state_attr('binary_sensor.meteoalarm_brabant','description')}}
<font color= {{alarm_color}}> [{{state_attr('binary_sensor.meteoalarm_brabant','attribution')}}]({{state_attr('binary_sensor.meteoalarm_brabant','web')}})</font>'

lovelace card content:

      content: >
        {% set alarm_color = state_attr('binary_sensor.meteoalarm_brabant','awareness_level').split(' ')[1].split(';')[0] %}
        ## <font color= {{alarm_color}}> {{state_attr('binary_sensor.meteoalarm_brabant','headline')}}</font>

        <font color= {{alarm_color}}><ha-icon icon= {{states('sensor.meteoalarm_icon')}}></ha-icon></font>

        <font color= {{alarm_color}}> **Severity:**</font> {{state_attr('binary_sensor.meteoalarm_brabant','severity')}}

        <font color= {{alarm_color}}> **Type:**</font> {{state_attr('binary_sensor.meteoalarm_brabant', 'awareness_type')}}

        <font color= {{alarm_color}}> **Description:**</font>

        {{state_attr('binary_sensor.meteoalarm_brabant','description')}}

        <font color= {{alarm_color}}> [{{state_attr('binary_sensor.meteoalarm_brabant','attribution')}}]({{state_attr('binary_sensor.meteoalarm_brabant','web')}})</font>

even though halfway startup it is already available:

Schermafbeelding 2021-05-17 om 14.10.17
Schermafbeelding 2021-05-17 om 14.10.173388×506 71.4 KB

should I do this:

      content: >
        {% if states.binary_sensor.meteoalarm_brabant is defined %}
        {% set alarm_color = state_attr('binary_sensor.meteoalarm_brabant','awareness_level').split(' ')[1].split(';')[0] %}
        ## <font color= {{alarm_color}}> {{state_attr('binary_sensor.meteoalarm_brabant','headline')}}</font>

        <font color= {{alarm_color}}><ha-icon icon= {{states('sensor.meteoalarm_icon')}}></ha-icon></font>

        <font color= {{alarm_color}}> **Severity:**</font> {{state_attr('binary_sensor.meteoalarm_brabant','severity')}}

        <font color= {{alarm_color}}> **Type:**</font> {{state_attr('binary_sensor.meteoalarm_brabant', 'awareness_type')}}

        <font color= {{alarm_color}}> **Description:**</font>

        {{state_attr('binary_sensor.meteoalarm_brabant','description')}}

        <font color= {{alarm_color}}> [{{state_attr('binary_sensor.meteoalarm_brabant','attribution')}}]({{state_attr('binary_sensor.meteoalarm_brabant','web')}})</font>
        {% else %} Initializing
        {% endif }

please have a look? thanks