<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def check_tweet(tweet, validation_checking=False):
 """ Ensures a tweet is valid and determines the type of format for the tweet. Args: tweet (dict/Tweet):
 the tweet payload validation_checking (bool):
 check for valid key structure in a tweet. """


    if "id" not in tweet:
        raise NotATweetError("This text has no 'id' key")

    original_format = is_original_format(tweet)

    if original_format:
        _check_original_format_tweet(tweet, validation_checking=validation_checking)
    else:
        _check_activity_streams_tweet(tweet, validation_checking=validation_checking)

    return original_format