RIC of delisted companies

Hello,

I have a list of permid, e.g.,

['4296383853', '4295908768'] 

I need to retrieve the correspnding RICs using the eikon API with python.

I tried this code:

df, err = ek.get_data(['4296383853', '4295908768'], ['TR.CompanyName', 'TR.RIC'])
df
print(df)

This is what I get:

   Instrument       Company Name   RIC
0  4296383853    Quantronix Corp  <NA>
1  4295908768  Advance Ross Corp  <NA>

Both companies have been delisted and their RIC from the Office search widget are, respectively:

['QUAN.O^J92', 'AROS.O^A96']

The problem is that I have a long list of companies like this, and I cannot search them manually, one by one.

I need to have these RICs to recover their historical stock prices. Is there a way to find these RICs using the eikon API?

Thank you.