In 3.7, SaveTool doesn’t behave as in 3.6 with legendItems: Legend renderers are shifted outside of the legend box.
It’s ok in 3.6 (I can’t post 2 images…).
from bokeh.plotting import figure, show
p = figure()
p.line([1, 2], [2, 1], line_width=4, legend_label="line")
show(p)