f1=[M[j] for j in range(len(target)) if (target.iloc[j]==1).bool()]
f0=[M[j] for j in range(len(target)) if (target.iloc[j]==0).bool()]
plt.hist(f1, bins=40, facecolor="red", alpha=0.3,label='Signal')
plt.hist(f0, bins=40, facecolor="green", alpha=0.3,label='Background')
plt.title('M')
plt.legend()
plt.show()
报错:numpy.bool_' object has no attribute 'bool'