I would like to have only the rows where "country_o" and "country_d" are available.
| country_o | country_d | values | 
|---|---|---|
| Italy | Turkiye | 123 | 
| NA | Turkiye | 87 | 
| Spain | NA | 93 | 
| Spain | Germany | 235 | 
I would like to have only the rows where "country_o" and "country_d" are available.
| country_o | country_d | values | 
|---|---|---|
| Italy | Turkiye | 123 | 
| NA | Turkiye | 87 | 
| Spain | NA | 93 | 
| Spain | Germany | 235 | 
