matplotlib图例:散点图的颜色不是我所期望的

import matplotlib.pyplot as plt

x = [1, 2, 3, 4, 5]
y = [2, 4, 6, 8, 10]
colors = ['red', 'green', 'blue', 'yellow', 'orange']

plt.scatter(x, y, color=colors)
plt.show()

import matplotlib.pyplot as plt
import numpy as np

x = np.random.rand(100)
y = np.random.rand(100)
colors = np.random.rand(100)

plt.scatter(x, y, c=colors, cmap='cool')
plt.colorbar()
plt.show()

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

x = np.random.rand(100)
y = np.random.rand(100)
colors = np.random.rand(100)

cmap = colors.ListedColormap(['red', 'green', 'blue'])
plt.scatter(x, y, c=colors, cmap=cmap)
plt.colorbar()
plt.show()