import matplotlib.pyplot as plt
from regions import CirclePixelRegion, PixCoord

region = CirclePixelRegion(PixCoord(x=0.3, y=0.42), radius=0.5)
artist = region.as_artist()

fig, ax = plt.subplots()
ax.set_aspect('equal')
ax.add_artist(artist)
ax.set_xlim([-0.5, 1])
ax.set_ylim([-0.5, 1])