def __init__(self, size, alpha):
super(PrioritizedReplayBuffer, self).__init__(size)<EOL>assert alpha >= <NUM_LIT:0><EOL>self._alpha = alpha<EOL>it_capacity = <NUM_LIT:1><EOL>while it_capacity < size:<EOL><INDENT>it_capacity *= <NUM_LIT:2><EOL><DEDENT>self._it_sum = SumSegmentTree(it_capacity)<EOL>self._it_min = MinSegmentTree(it_capacity)<EOL>self._max_priority = <NUM_LIT:1.0><EOL>
Create Prioritized Replay buffer.

        Parameters
        ----------
        size: int
            Max number of transitions to store in the buffer. When the buffer
            overflows the old memories are dropped.
        alpha: float
            how much prioritization is used
            (0 - no prioritization, 1 - full prioritization)

        See Also
        --------
        ReplayBuffer.__init__