How to set line color with sellf-defined color map when using plot_connectome

I would like to draw a connectome plot using self-defined color map for the links.

The following is my code. Here, sm defined a colormap but I can not use it in built-in parameter edge_cmap, like edge_cmap = sm.

Moreover, I can not use edge_kwargs to manually define colors of all the links, either. I tried edge_kwargs = {"color": sm.to_rgba(strength)}, but it failed as it returned an rgb array can not be a valid color.

import numpy as np
import random
import matplotlib.colors as mplc
from matplotlib import cm

connectivity2 =  np.zeros([len(roilist),len(roilist)])
strength = [random.random() for _ in range(len(roilist))]
connectivity2[:,1] = strength
connectivity2[1,:] = strength

cmap = mplc.ListedColormap(["steelblue","#FF4F00"])
sm = cm.ScalarMappable(norm = plt.Normalize(np.min(strength),
                       cmap = cmap)

plot1_2 = plot_connectome(connectivity2,
                       edge_kwargs = {"linewidth":1.5,
                       display_mode = "z",
                       alpha = 0.2)