Revert back to isinstance check for iris cube

Author: Russell Manser

xarray/convert.py

@@ -10,6 +10,7 @@
 from .core import duck_array_ops
 from .core.dataarray import DataArray
 from .core.dtypes import get_fill_value
+from .core.pycompat import dask_array_type
 
 cdms2_ignored_attrs = {"name", "tileIndex"}
 iris_forbidden_keys = {
@@ -255,8 +256,6 @@ def from_iris(cube):
     """
     import iris.exceptions
 
-    from xarray.core.pycompat import is_duck_dask_array
-
     name = _name(cube)
     if name == "unknown":
         name = None
@@ -291,7 +290,7 @@ def from_iris(cube):
     cube_data = cube.core_data() if hasattr(cube, "core_data") else cube.data
 
     # Deal with dask and numpy masked arrays
-    if is_duck_dask_array(cube_data):
+    if isinstance(cube_data, dask_array_type):
         from dask.array import ma as dask_ma
 
         filled_data = dask_ma.filled(cube_data, get_fill_value(cube.dtype))