code: def test_watershed(dtype):
      St = S.astype(dtype)
      Mt = M.astype(int)
      W = mahotas.cwatershed(2 - St, Mt)
      if hasattr(sys, "getrefcount"):
          assert sys.getrefcount(W) == 2
      assert np.all(
          W
          == np.array(
              [
                  [1, 1, 1, 1],
                  [1, 1, 1, 1],
                  [1, 1, 1, 1],
                  [2, 2, 1, 1],
                  [2, 2, 2, 2],
                  [2, 2, 2, 2],
                  [2, 2, 2, 2],
              ]
          )
      )
  
file_path: mahotas/mahotas/tests/test_watershed.py
imports: import numpy
  import mahotas
  import mahotas
  import sys
  import pytest
label_desc: Use image node_id 1 for calling a global function with example usage: test_watershed(dtype) without return types