You forget the tanh function in the last computation in the part of def bottom_data_is(): about lstm HOT 4 OPEN

    def top_diff_is(self, top_diff_h, top_diff_s):
        # notice that top_diff_s is carried along the constant error carousel
        ds = self.state.o * top_diff_h + top_diff_s
        do = self.state.s * top_diff_h
        di = self.state.g * ds
        dg = self.state.i * ds
        df = self.s_prev * ds

ds = self.state.o *(1-self.state.s^2)* top_diff_h + top_diff_s;
do = np.tanh(self.state.s) * top_diff_h