pandas expand rows with alternative names (multiple and change rows)

I’m trying to format following dataframe (it can be copied to clipboard and read by pd ):

Given the dictionary where for each country there is a list of alternative names, I am trying to "explode" values with duplicate rows where country values are updated.
Dictonary to update country_names:

{
    'UAE':['United Arab Emirates', 'UAE'],
    'Rep of Tunisia': ['Tunisia','Rep of Tunisia']
}

desired result:

It seemed like an easy thing but I stuck, any help appreciated.

>Solution :

You can map your dictionary, then explode:

out = (df.assign(country=df['country'].map(country_names))
         .explode('country', ignore_index=True)
       )

output:

                country      period
0  United Arab Emirates  2022-01-01
1                   UAE  2022-01-01
2               Tunisia  2022-10-01
3        Rep of Tunisia  2022-10-01