input: Write a python function to split a list of tweets and labels into training and test datasets using sklearn's train_test_split function. 
  assert len(X_train) == 3 and len(y_train) == 3
  assert len(X_test) == 1 and len(y_test) == 1
output: def split_data(tweets, labels):
      from sklearn.model_selection import train_test_split
      
      X_train, X_test, y_train, y_test = train_test_split(tweets, labels, test_size=0.25, random_state=42)
      
      return X_train, X_test, y_train, y_test