How can I save the current date without overwriting it? Pandas Python

Question

I have a .csv database with names. Every month it is updated and I've created a code that breaks down the names that have left and those that have entered the database, generating two .csv's at the end: a list of those that have been inserted into the database (inserted.csv) and those that have been removed from the database (removed.csv).

database

In the withdrawals, I have to create a column indicating the exact date on which the code was executed to generate the withdrawals.

An example of what I would like and a hypothetical situation to put it in context: 01/10 I run the code, which returns me the list of those removed from the base + the date of the day I ran it.

example

The other day, I discovered that the base list had been updated and other names had been removed, so I ran my code again.

That's what I hope to find:

example 2

The list of withdrawals with the date of the previous execution plus the names and date of the most recent time I used the code.

I want to be able to have a record of the date I executed the code without overwriting past dates.

I've already tried using this code, but to no avail.

cod fail

my code:

base = pd.read_csv('cadastro_de_empregadores.csv', sep= ';', encoding="latin-1", skiprows= 5)

copia_base = pd.read_csv('copia_base.csv', sep= ';', encoding="latin-1")

base.dropna(axis = 1, how = 'all', inplace= True)

inseridos = copia_base[~copia_base['CNPJ/CPF'].isin(base['CNPJ/CPF'])]

retirados = base[~base['CNPJ/CPF'].isin(copia_base['CNPJ/CPF'])]