How to use variables with initial function?

[phwang4]

I've created a flow in colang that will execute the initial function with the ticketType variable that's passed in by the user asking the question. For example, I'd like to be able to ask "Give me P1 tickets" and so on where P1 would be the ticketType. I wasn't able to find anything for this in the documentation but I tried to use this colang

define user ask tickets
    "Give me $ticketType tickets"

but with little success. For reference here is the entire thing.

colang_content = """
# define limits
define user ask tickets
    "Give me $ticketType tickets"

define bot answer ticketInfo
    bot report ticketInfo

define flow tickets
    user ask tickets
    $ticketInfo = execute get_ticket_info(ticketType=$ticketType)
    bot answer ticketInfo

# here we use the chatbot for anything else
define flow
    user ...
    bot greeting
"""
yaml_content = """
models:
- type: main
  engine: openai
  model: text-davinci-003
"""