code: def main():
      
      if len(sys.argv) < 2:
          print("Usage: {} SCOPE...".format(sys.argv[0]))
          return 1
  
      authenticator = prawcore.TrustedAuthenticator(
          prawcore.Requestor("prawcore_refresh_token_example"),
          os.environ["PRAWCORE_CLIENT_ID"],
          os.environ["PRAWCORE_CLIENT_SECRET"],
          os.environ["PRAWCORE_REDIRECT_URI"],
      )
  
      state = str(random.randint(0, 65000))
      url = authenticator.authorize_url("permanent", sys.argv[1:], state)
      print(url)
  
      client = receive_connection()
      data = client.recv(1024).decode("utf-8")
      param_tokens = data.split(" ", 2)[1].split("?", 1)[1].split("&")
      params = {
          key: value
          for (key, value) in [token.split("=") for token in param_tokens]
      }
  
      if state != params["state"]:
          send_message(
              client,
              "State mismatch. Expected: {} Received: {}".format(
                  state, params["state"]
              ),
          )
          return 1
      elif "error" in params:
          send_message(client, params["error"])
          return 1
  
      authorizer = prawcore.Authorizer(authenticator)
      authorizer.authorize(params["code"])
  
      send_message(client, "Refresh token: {}".format(authorizer.refresh_token))
      return 0
docs: Provide the program's entry point when directly executed.