alien_3 = {'x_position': 0, 'y_position': 25, 'speed': 'medium'}
print(f"Original position {alien_3['x_position']}")
# Determine how far to move the alien based on its current speed
if alien_3['speed'] == 'slow':
    x_increment = 1
elif alien_3['speed'] == 'medium':
    x_increment = 2
else:
    # This must be a fast alien
    x_increment = 3        
# The new position is the old position plus the increment
alien_3['x_position'] = alien_3['x_position'] + x_increment
print(f"New position: {alien_3['x_position']}")