from typing import List, Optional


class CrewAgent:
    def __init__(self, role: str, goal: str, backstory: str):
        self.role = role
        self.goal = goal
        self.backstory = backstory

    def execute_task(self, task: str) -> str:
        raise NotImplementedError("CrewAI agent not yet implemented")


def get_trading_crew():
    raise NotImplementedError("Trading crew not yet implemented")