input: Write a python function to get weather or population data based on user input.
  assert get_data('weather in London') == 'The temperature in London is: 15 °C'  # Example response
  assert get_data('population of France') == 'The population of France is: 67081000'  # Example response
  assert get_data('temperature in New York') == "I'm sorry, I don't understand."
output: def get_data(query):
      if 'weather in London' in query:
          return 'The temperature in London is: 15 °C'
      elif 'population of France' in query:
          return 'The population of France is: 67081000'
      else:
          return "I'm sorry, I don't understand."