Here is a full example which may help also referenced from the same page shared previously.

from symphony.bdk.core.activity.command import CommandContext
from symphony.bdk.core.config.loader import BdkConfigLoader
from symphony.bdk.core.symphony_bdk import SymphonyBdk


async def run():
    async with SymphonyBdk(BdkConfigLoader.load_from_symphony_dir("config.yaml")) as bdk:
        activities = bdk.activities()
        messages = bdk.messages()

        @activities.slash("/buy {$ticker} {quantity}")
        async def on_echo_mention(context: CommandContext):
            ticker = context.arguments.get_cashtag("ticker").value # can also be retrieved with context.arguments.get("ticker").value
            quantity = context.arguments.get_string("quantity")
            
            message = f"Buy ticker {ticker} with quantity {quantity}"

            await messages.send_message(context.stream_id, f"<messageML>{message}</messageML>")

So below is an example in Python on how your bot can extract arguments from a Symphony chat message.

@activities.slash("/echo {first_string_argument} {second_string_argument}")
async def on_echo_string_arguments(context: CommandContext):
#Get string argument with get_string
first_string_argument = context.arguments.get_string("first_string_argument")
# Get string argument with get_as_string
second_string_argument = context.arguments.get_as_string("second_string_argument")
message = f"Received arguments: {first_string_argument} and {second_string_argument}"
await messages.send_message(context.stream_id, f"<messageML>{message}</messageML>")

In the example we are just returning the values back to the user in the form of a Symphony message. But you could invoke your own business logic (including a Selenium web driver class) to carry out another action.