Incorrect code does not throw an exception

[ASmirnov-HORIS]

The following code is incorrect and should produce an error:

from lets_plot import *
LetsPlot.setup_html()
p = ggplot() + geom_point(x=0, y=0)
q = ggplot() + geom_point(x=1, y=1)
p + q

But it just draws a picture:

[alshan]

If we show two plots it could be a feature )