I am trying to change the column name of one set of duplicate columns in the dataframe. I form the dataframe from two different csv files after a bunch of pre-processing.

`merged_df.columns` is this:

```
Index(['PortfolioID', 'FirmID', 'PC_City', 'PC_State', 'PC_Country',
   'Investment_Date', 'Exit_Date', 'Transaction_Comments', 'PC_City', 
   'PC_State', 'PC_Country',
   'fundSize'],
  dtype='object')

```

The first set of `PC_City, PC_State, PC_Country` is for portfolio companies and the next set is for the firms. I tried [this](https://datascience.stackexchange.com/a/41466/59059) but made both the sets same. Then I saw [this](https://stackoverflow.com/a/39986959/4060622) but it can be done only when importing the csv. [This](https://stackoverflow.com/questions/11346283/renaming-columns-in-pandas) doesn't talk about duplicates.

Is there any way I can achieve this? **Mods please help with the editing.**