PYTHON painting three-dimensional map

import matplotlib.pyplot as plt
from mpl_toolkits.mplot3d import Axes3D
import numpy as np

#bbb=[1 if (i <=0.5 or i >=1.5)  else 0 for i in D

def fun(x, y):
    value= x**2+y**2


    return value

fig1 = plt.figure()
ax = Axes3D(fig1)
X, Y = np.mgrid[-4:4:40j, -4:4:40j]
Z1 = fun(X, Y)
numsize=len(Z1)
Z=Z1
for i in range(40):
    for j in range(40):
        if (Z1[i][j]<0.5 ):
            Z[i][j]=1
        elif (Z1[i][j]>11):
            Z[i][j]=1
        else:
            Z[i][j]=0
# for i in range(len(Z1)):
#     if lis[i] in str:
#         lis[i]='-'
# print(lis)



# Z=[1 if (i <=10 or i >=20)  else 0 for i in Z1]

# plt.title("This is main title")
ax.plot_surface(X, Y, Z, rstride=1, cstride=1, cmap=plt.cm.coolwarm, alpha=0.5)
ax.set_xlabel('u', color='b')
ax.set_ylabel('v', color='r')
ax.set_zlabel('H(u,v)', color='g')
plt.show()