def remove_blanks(df, token_col="text_tokens"):
    """
    removes blank elements in tokenised text column in df if there are non blank elements  in that list
    Args:
        df (DataFrame): dataframe containing tokenised text
        token_col (string): column in df containitng tokenised text


    Returns: df with blank words inside tokenised lists removed

    """
    proc_words = []
    for words in df[token_col]:
        # is list not empty?
        if words:
            # remove empty strings
            proc_words.append([word
                               for word in words
                               if word
                               ])
        else:
            # add empty list if list is empty, to keep list size the same
            proc_words.append([])

    df[token_col] = proc_words
    return df