Specifically its used for the African species (blandingii and pulverulenta) since they do have some slight differences from the Australasian Boiga. The validity is pretty shakey though and Boiga is typically used for all forms, whether African or Asian.
If the snake in question is well over a meter, then its almost certainly Boiga blandingii (they get over three!). If its less than a meter and has pink flower like markings on the side, then its most likely Boiga pulverulenta.
Posting a picture would allow for definitive ID 
Cheers
BGF
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