def categorize_arrests(dataframe):
    """categorizes arrests into boolean 1 if 1+ arrests, 0 if no arrests

    Args:
        dataframe: a pandas dataframe with column 'n_arrests' to be transformed
    
    Returns:
        cat_df: a copy of the original dataframe with column 'n_arrests' filled
        with 1 and 0 for arrest(s)/no arrests
    """
    cat_df = dataframe.copy()
    cat_df['n_arrests'] = cat_df['n_arrests'].fillna(value=0)
    cat_df['n_arrests'] = cat_df['n_arrests'].astype(int)
    cat_df.loc[cat_df['n_arrests'] > 0, 'n_arrests'] = 1
    return cat_df