<｜begin▁of▁sentence｜>### Instruction:
As an event planner, you have been tasked with organizing a corporate conference. Your client has provided you with a PrecalculatedPalette, which is a list of colors representing the corporate brand. They want these colors to be showcased in the conference promotional materials. You need to demonstrate how to use a matplotlib Axes instance to plot these colors and showcase it in a visually appealing manner for their approval.
### Response:
from igraph import Plot, PrecalculatedPalette
import matplotlib.pyplot as plt

# Define a precalculated palette.
precalculated_palette = PrecalculatedPalette(['red', 'green', 'blue'])

# Create a plot with matplotlib
fig, ax = plt.subplots()

# Plot the colors from the palette.
# Note: __plot__ is an internal method and it should be used indirectly
# through the Plot class or with care as API can change.
precalculated_palette.__plot__(ax)

# Show the plot with the colors
plt.show()
<|EOT|>
