Matplotlib.colors.from_levels_and_colors() in Python

import numpy as np
import matplotlib.pyplot as plt
import matplotlib.colors

data1 = 3 * np.random.random((10, 10))
data2 = 5 * np.random.random((10, 10))

levels = [0, 1, 2, 3, 4, 5]
colors = ['red', 'brown',
          'yellow', 'green',
          'blue']
cmap, norm = matplotlib.colors.from_levels_and_colors(levels, 
                                                      colors)

fig, axes = plt.subplots(ncols = 2)

for ax, data in zip(axes, [data1, data2]):
    im = ax.imshow(dat, 
                   cmap = cmap,
                   norm = norm, 
                   interpolation ='none')
    
    fig.colorbar(im, ax = ax, orientation ='horizontal')
    
plt.show()

import numpy as np
import matplotlib.pyplot as plt
from matplotlib.colors import from_levels_and_colors

nvals = np.random.randint(2, 20)
data = np.random.randint(0, nvals, 
                         (10, 10))

colors = np.random.random((nvals, 3))
# Make the colors pastels...
colors = colors / 2.5 + 0.55

levels = np.arange(nvals + 1) - 0.5
cmap, norm = from_levels_and_colors(levels,
                                    colors)

fig, ax = plt.subplots()
im = ax.imshow(data,
               interpolation ='nearest', 
               cmap = cmap, 
               norm = norm)

fig.colorbar(im, ticks = np.arange(nvals))
plt.show()