This tune of Emerante de Pradines is the typical example why I believe strongly and honestly that the musical expressions of our feelings were spoiled by western musical influence.
It is being played on the key of C minor in the original version which can be seen on Youtube below:
The iv chord is the next chord that is played with a strong emphasis. Though it is not a wrong chord, the Bb minor conveys much more our feelings and this ties us to Brazilian music where we do find also this Minor 7th chord to Minor I chord progression. Moreover, the Natif concept emphasizes also the Minor 7th chord while reproducing the vaksin intervals at the same time.
Here are the scores as suggested by the Natif concept:
Lègba N a Konsole