code: def validate_a_time_filter(self, value):
          
          if value:
              try:
                  utils.parse_datetime_range(value)
              except Exception as e:
                  raise serializers.ValidationError(e.message)
  
          return value
docs: Would be for example: [2013-03-01 TO 2013-04-01:00:00:00] and/or [* TO *]