表: Users+---------------+---------+|ColumnName|Type|+---------------+---------+|user_id|int||name|varchar||mail|varchar|+---------------+---------+user_id是该表的主键（具有唯一值的列）。该表包含了网

2882.删去重复的行DataFramecustomers+-------------+--------+|ColumnName|Type|+-------------+--------+|customer_id|int||name|object||email|object|+-------------+--------+在DataFrame中基于email列存在一些重复行。编写一个