'Args:
exp (Experience):'

def append(self, exp):

    if (self._curr_size < self.max_size):
        self._assign(self._curr_pos, exp)
        self._curr_pos = ((self._curr_pos + 1) % self.max_size)
        self._curr_size += 1
    else:
        self._assign(self._curr_pos, exp)
        self._curr_pos = ((self._curr_pos + 1) % self.max_size)
    if exp.isOver:
        self._hist.clear()
    else:
        self._hist.append(exp)
