Try to fix the Flag sensor.

config/packages/holiday.yaml

@@ -39,14 +39,14 @@ sensor:
       {{ holiday }}
 
   - platform: rest
-    resource: http://www.webcal.fi/cal.php?id=335&format=json&start_year=current_year&end_year=2018&tz=America%2FNew_York
+    resource: http://www.webcal.fi/cal.php?id=335&format=json&start_year=current_year&end_year=2020&tz=America%2FNew_York
     name: Flag
     scan_interval: 14400
     value_template: >-
       {% set is_flag_day = False %}
       {%- for day_val in value_json -%}
         {% set now_string = now().strftime('%Y-%m-%d') %}
-        {%- if day_val.date == now_string and day_val.flag_day == 1-%}
+        {%- if day_val.date==now_string and day_val.flag_day==1 -%}
           {% set is_flag_day = True %}
         {%- endif -%}
       {% endfor %}