def tokenise_text_col(df, text_col="text", suffix="_tokens", return_col_name = False):

    """
    wrapper function for a list comprehenshion that tokenises a text column
    in df, returning df with a new column containing tokenised text
    Args:
        df: dataframe with text data
        text_col: column with text data
        suffix: to add to text_col to give the column name containing tokenised text
        return_col_name: flag to return col name or not
    Returns:
        pandas dataframe with new column containing tokenised text and the column name if
        return_col_name flag is true
    """
    col_name = text_col + suffix
    df[col_name] = [text.split(" ")
                             for text in df[text_col].astype(str).tolist()
                             ]
    if return_col_name:
        return df, col_name
    else:
        return df