code: def draw_lines(cvs, points, antialias):
      """Draw multiple line.
  
      Parameters
      ----------
      cvs: canvas
        A Datashader canvas
      points: list of tuple of tuple
        The lines to render as a list of tuples, where each tuple represents a
        line consisting of two tuples each containing two scalars describing the
        two vertices of the line.
      antialias: boolean
        To anti-alias or not is the question
  
      Returns
      -------
      agg: A Datashader aggregator (xarray)
      """
      aggs = []
      for (x1, y1), (x2, y2) in points:
          aggs.append(draw_line(cvs, (x1, y1), (x2, y2), antialias))
      return xr.concat(aggs, "stack").sum(dim="stack")
  
imports: import os
  import xarray
  import datashader
  import pandas
  import numpy
  import pytest
label_desc: Use image node_id 2 for calling a global function with example usage: draw_lines(cvs, points, antialias) and returns: xr