input: 
  from typing import List
  
  def get_current_datetime_str() -> str:
      """ Get the current date and time as a string formatted as "YYYY-MM-DD HH:MM:SS".
      >>> get_current_datetime_str()
      '2023-10-05 14:30:45'  # This will vary depending on the current date and time.
      """
  
output:     from datetime import datetime
      return datetime.now().strftime("%Y-%m-%d %H:%M:%S")