def __init__(self, data=[]):
        """create a new priority Queue (build heap structure)"""
        self._a = [None] * (1 + len(data))
        for i in range(1, len(self._a)):
            self._bubbleup(i, data[i-1])
create a new priority Queue (build heap structure)
recipes/Python/81693_Heapbased_priority_queue/recipe-81693.py