def filter_after_preprocess(processed_tokens, retained_dict):

    """
    Removes any tokens not in the retained_dict from a list of processed tokens 
    
    Argument(s): processed_tokens  - a list of pre-processed token
                 retained_dict     - a token-frequency dictionary of tokens retained 
                                          after removing tokens up to min_threshold frequency
    
    Output:      filtered          - a list of tokens remaining after filtering out those that
                                     are absent from retained_dict
    """
    filtered = []

    for token in processed_tokens:
        if token in retained_dict.keys():
            filtered.append(token)

    return filtered