input: Write a python function to respond to a message based on predefined responses.
  assert respond("hi") == "Hello! I am a bot. I'm here to help you."
  assert respond("How are you") == "I'm doing well, thanks for asking!"
  assert respond("Are you happy?") == "I'm just a bot, so I don't have feelings."
  assert respond("What can you do?") == "I can answer questions about myself, like who created me or what language I'm written in."
  assert respond("What's your name?") == "I'm sorry, I don't understand. Please ask me something else."
output: def respond(message):
      responses = {
          "hi": "Hello! I am a bot. I'm here to help you.",
          "How are you": "I'm doing well, thanks for asking!",
          "Are you happy?": "I'm just a bot, so I don't have feelings.",
          "What can you do?": "I can answer questions about myself, like who created me or what language I'm written in.",
      }
      return responses.get(message, "I'm sorry, I don't understand. Please ask me something else.")