input: Write a python function to sum a list of numbers from query parameters in a Flask route.
  assert get_sum({"numbers": ["1", "2", "3"]}) == "6"
  assert get_sum({"numbers": ["10", "20", "30"]}) == "60"
  assert get_sum({"numbers": ["5", "15", "25"]}) == "45"
output: from flask import Flask, request
  
  app = Flask(__name__)
  
  @app.route('/sum')
  def get_sum():
      numbers = request.args.getlist('numbers')
      total = sum(map(int, numbers))
      return str(total)