Custom Search Command pass arguments as subsearch

[Unige2021]

I need to pass two values to my Custom Search Command.

These are my Options:

x = Option(require=True)
y = Option(require=True)

 I want to pass those via a subsearch. I tried:

my_custom_search x=[search type="GGA" | stats latest(latitude) as x, latest(longitude)as y]

 However Splunk complains about missing y options!

How can I achieve what I wont?

Thank you in advance!