pandas: find top n unique values in each column

uniques.py

def df_column_unique_values(df, top_n = 5):
    for col_name, values in df.iteritems():
        col_value_counts = values.value_counts()
        print(f"{col_name} : {len(col_value_counts)}")
        col_value_count_list = [
            "'" + str(c) + "'" + ":" + str(n) for c, n in sorted(
                col_value_counts.items(),
                key=lambda kv: kv[1],
                reverse=True
            )
        ]
        print(", ".join(col_value_count_list[:min(len(col_value_count_list), top_n)]))
        # print ('\\n')