code: def test_cat_dshapes():
      # concatenating 1 dshape is a no-op
      dslist = [dshape("3 * 10 * int32")]
      assert datashape.cat_dshapes(dslist) == dslist[0]
      # two dshapes
      dslist = [dshape("3 * 10 * int32"), dshape("7 * 10 * int32")]
      assert datashape.cat_dshapes(dslist) == dshape("10 * 10 * int32")
  
file_path: datashader/datashader/datashape/tests/test_util.py
imports: import pytest
  from datashader import datashape
  from datashader.datashape import dshape, has_var_dim, has_ellipsis
label_desc: Use image node_id 1 for calling a global function with example usage: test_cat_dshapes() without return types