'Sets the rounding decision.
Sets the rounding decision, and returns the current (previous)
rounding decision.  Often used like:
context = context._shallow_copy()
# That so you don\'t change the calling context
# if an error occurs in the middle (say DivisionImpossible is raised).
rounding = context._set_rounding_decision(NEVER_ROUND)
instance = instance / Decimal(2)
context._set_rounding_decision(rounding)
This will make it not round for that operation.'

def _set_rounding_decision(self, type):

    rounding = self._rounding_decision
    self._rounding_decision = type
    return rounding
