docs: def round(self, digits=0):
          """ Round the elements of the given vector to the given number of digits. """
          # Meant as a way to clean up Vector.rotate()
          # For example:
          #   V = Vector(1,0)
          #   V.rotate(2*pi)
          #   
          #   V is now <1.0, -2.4492935982947064e-16>, when it should be 
          #   <1,0>. V.round(15) will correct the error in this example.
          
          self.x = round(self.x, digits)
          self.y = round(self.y, digits)