code: def get_setting(context, key, default_val="", as_key=None):
      
      if ("%s" % default_val).startswith('$.'):
          default_val = getattr(settings, default_val[2:])
      val = getattr(settings, key, default_val)
      if not as_key:
          return val
      context[as_key] = val
      return ''
docs: get val form settings and set to context
        {% load lbutils %}
        {% get_setting "key" default_val "as_key" %}
        {{ as_key }}
        if as_key is None, this tag will return val