input: Write a python function to return the current time in a specified timezone.
  assert isinstance(get_current_time('America/Chicago'), str)
  assert isinstance(get_current_time('Asia/Tokyo'), str)
  assert isinstance(get_current_time('Europe/London'), str)
output: def get_current_time(timezone: str) -> str:
      from datetime import datetime
      import pytz
      
      tz = pytz.timezone(timezone)
      current_time = datetime.now(tz)
      return current_time.strftime('%Y-%m-%d %H:%M:%S')