市松模様塗装のpython

import matplotlib
color1=(1,1,1)
color2=(247/255,220/255,111/255)

mat=np.zeros((8,8))
for i in range(8):
    for j in range(8):
        if (i+j)%2==0:
            mat[i,j]=1
        else:
            mat[i,j]=-1

my_cmap=matplotlib.colors.LinearSegmentedColormap.from_list('my_camp',[color1,color2],2)
cs=plt.imshow(mat,cmap=my_cmap)

plt.xticks(np.linspace(0,8,8,endpoint=False),('a','b','c','d','e','f','g','h'),fontsize=20)
plt.yticks(np.linspace(0,8,8,endpoint=False),('1','2','3','4','5','6','7','8'),fontsize=20)
plt.tick_params(bottom=False,left=False,labeltop=True,labelright=True)
plt.show()