simplify __array_ufunc__ check

xarray/core/arithmetic.py

@@ -16,7 +16,7 @@
 from .common import ImplementsArrayReduce, ImplementsDatasetReduce
 from .ops import IncludeCumMethods, IncludeNumpySameMethods, IncludeReduceMethods
 from .options import OPTIONS, _get_keep_attrs
-from .pycompat import dask_array_type
+from .pycompat import is_duck_array
 
 
 class SupportsArithmetic:
@@ -33,20 +33,21 @@ class SupportsArithmetic:
 
  # TODO: allow extending this with some sort of registration system
  _HANDLED_TYPES = (
- np.ndarray,
  np.generic,
  numbers.Number,
  bytes,
  str,
- ) + dask_array_type
+ )
 
  def __array_ufunc__(self, ufunc, method, *inputs, **kwargs):
  from .computation import apply_ufunc
 
  # See the docstring example for numpy.lib.mixins.NDArrayOperatorsMixin.
  out = kwargs.get("out", ())
  for x in inputs + out:
- if not isinstance(x, self._HANDLED_TYPES + (SupportsArithmetic,)):
+ if not is_duck_array(x) and not isinstance(
+ x, self._HANDLED_TYPES + (SupportsArithmetic,)
+ ):
  return NotImplemented
 
  if ufunc.signature is not None: