thank you very much for your answer
It is a Boa constrictor. Like the comment mentioned, the geographic location helps. If you are in southern Central America or South America, it's probably native; elsewhere, it's probably someone's escaped pet. They are non-venomous, but will defend themselves if they are threatened or harassed by hissing and striking. They have many, small, very sharp teeth that could easily lacerate your skin, but not deeply.
These snakes populations are very, very reduced, so please do not harm it since it does not want to interact with you at all. They eat rodents and other pests, so it's good to keep their numbers up. They are also magnificently beautiful and have very interesting biology (for example, they give live birth and have pits on their faces that help them sense infrared!).
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