code: def test_is_coordsys_maker():
      # Test coordinate system check
      cm = CoordSysMaker("xyz")
      assert is_coordsys_maker(cm)
  
      class C:
          pass
  
      c = C()
      assert not is_coordsys_maker(c)
      c.coord_names = []
      assert not is_coordsys_maker(c)
      c.name = ""
      assert not is_coordsys_maker(c)
      c.coord_dtype = np.float64
      assert not is_coordsys_maker(c)
  
      # Distinguish from CoordinateSystem
      class C:
          coord_names = []
          name = ""
          coord_dtype = np.float64
  
          def __call__(self):
              pass
  
      assert is_coordsys_maker(C())
      assert not is_coordsys_maker(CoordinateSystem("ijk"))
  
imports: from types import SimpleNamespace
  import numpy
  import pytest
  from ..coordinate_system import CoordinateSystem, CoordinateSystemError, CoordSysMaker, CoordSysMakerError, is_coordsys, is_coordsys_maker, product, safe_dtype
label_desc: Use image node_id 18 for calling a global function with example usage: test_is_coordsys_maker() without return types