Is there a way for me to write my own functions and perform them inplace like most methods in Pandas

I would like my functions to perform certain operations to my pandas DataFrame in place. Most methods in Pandas have the inplace methods. At the moment, I would like to use the idea of the inplace functionality to my function to make this particular function perform in place in order to avoid me reassigning it or thinking I have re-assigned it.

Here is my code in action:

def populate_df(df_month, working_df, Win_ID ="WIN_ID"):
    details = ["Type", "protype", "direction", "per_typ", "produkt_name"]

    for detail in details:
        working_df[detail] = [dict(zip(df_month[Win_ID], df_month[detail]))[id] for id in working_df[Win_ID]]

    return working_df

Here I am trying to apply the function

df1 = travel_details(df_month = Dec2019, working_df=df1)

I would like to do this and it updates my dataframe instead of the assignment

travel_details(df_month = Dec2019, working_df=df1)

or create a boolean like update_inplace in the function that updates when true like:

travel_details(df_month = Dec2019, working_df=df1, update_inplace=True)