Unable to read the value from string template

Hi, I've a tickscript. It works fine but I'd want to pass and read the string templates, those wrapped in the curly braces together when I execute the python script.

```
var message = 'ALERT! CHECK YOUR {{ index .Tags "hostname" }}
EXPECTED VALUE: {{ index .Fields "past.p" }} | CURRENT VALUE: {{ index .Fields "current.c" }} '

var current = batch
|query('SELECT non_negative_derivative(mean("ifHCInUcastPkts"), 5m) AS "c" FROM "router-test"."autogen"."interface" WHERE time > now() - 30m AND time < now() GROUP BY time(5m)')
.period(30m)
.every(5m)
.groupBy(time(5m), *)
.align()
|where(lambda: "hostname" == 'router1')

var past = batch
|query('SELECT non_negative_derivative(mean("ifHCInUcastPkts"), 5m) AS "p" FROM "router-test"."autogen"."interface" WHERE time > now() - 1h AND time < now() GROUP BY time(5m)')
.period(1h)
.every(5m)
.groupBy(time(5m), *)
.align()
|where(lambda: "hostname" == 'router1')

var trigger = past
|join(current)
.as('past', 'current')
|eval(lambda: float("current.c" - "past.p"))
.keep()
.as('value')
|alert()
.crit(lambda: "value" > 100)
.exec('/usr/bin/python', 'dosth.py', message)
```

**desired result**: message is sent to my python script and is able to display the text from python as
'ALERT! CHECK YOUR router1, EXPECTED VALUE: 200 | CURRENT VALUE: 400 '

**current result**: message is displayed as it is from python.
'ALERT! CHECK YOUR {{ index .Tags "hostname" }}
EXPECTED VALUE: {{ index .Fields "past.p" }} | CURRENT VALUE: {{ index .Fields "current.c" }} '

I'm new to this, please help. Thank you

Start with the alert().exec('/usr/bin/python', 'dosth.py', message) call in the Tickscript and inspect how dosth.py receives its argument. Reproduce the alert with the shown message template, then verify that the script receives rendered tag and field values rather than the literal template text.

Written by the indexing model from the issue text.