I started learning manim and I hope you could help me understand how this code works
class Line_1(Scene):
    def construct(self):
        path = Line(LEFT*5,RIGHT*5,stroke_opatity=0.5)
        path.points[1:3] += UP*2
        self.add(path)
When I run the code I get this:

However I do not know how to interpret this "path.points[1:3] += UP*2" What does it mean .points[1:3]?
Thanks in advance
 
    