input: Write a python function to sum two numbers from a dictionary and return the result.
  assert sum_numbers({'num1': 1, 'num2': 2}, None)['body'] == 3
  assert sum_numbers({'num1': 10, 'num2': 5}, None)['body'] == 15
  assert sum_numbers({'num1': -1, 'num2': 1}, None)['body'] == 0
output: def sum_numbers(event, context):
      return {'body': event['num1'] + event['num2']}