perlin: remove unused import and fix import ordering

.claude/sweep-style-state.csv

@@ -14,6 +14,7 @@ interpolate-kriging,2026-06-04,2916,MEDIUM,1;4,"flake8 E128 x2: continuation-lin
 mcda,2026-06-10,3143,HIGH,3;4,F401 dead function-local warnings import in standardize.py; isort drift in weights.py combine.py __init__.py; flake8 otherwise clean; Cat 5 greps clean; fixed via PR for #3143
 morphology,2026-06-20,3400,HIGH,3;4,"F401 xr/has_cuda_and_cupy/not_implemented_func + F841 size (dead); isort ordering. /rockout PR off issue 3400. flake8+isort clean, 74 tests pass."
 multispectral,2026-06-20,3428,HIGH,3;4,F401 unused not_implemented_func (Cat3 HIGH); isort dataset_support before utils (Cat4 MEDIUM); Cat1/2/5 clean; fixed via #3428
+perlin,2026-06-23,,HIGH,3;4,"Cat3 F401: unused not_implemented_func import from xrspatial.utils (refactor leftover, not re-exported; __init__ exports only perlin). Cat4 isort: utils from-import reflowed to line_length=100 after the name was dropped. No Cat1/2/5 (grep clean: no bare except, mutable defaults, ==None/True, or shadowed builtins). flake8+isort clean after fix; import smoke test ok; 12 perlin tests pass (CUDA available). GitHub issues disabled on repo so no issue filed; fix on deep-sweep branch + PR."
 polygon_clip,2026-06-10,3184,HIGH,3;4,"Cat 3 F401: dropped unused typing imports Sequence/Tuple/Union (line 10, only Optional used) and the dead 'import cupy' inside the _apply_mask dask+cupy closure (line 245); the other 'import cupy' at line 261 is used (cupy.asarray) and kept. None re-exported (__init__ re-exports only clip_polygon). Cat 4 isort: reflowed the 5-name xrspatial.utils from-import block to line_length=100. Cat 1/2/5 grep clean (no E/W codes, no bare except, mutable defaults, ==None/True, or shadowed builtins). flake8+isort clean after fix; 23 test_polygon_clip tests pass. PR open."
 polygonize,2026-05-27,2534,HIGH,1;3;4,"F401 line 58 (is_cupy_array unused, not re-exported). E127 lines 83/88 (overload continuation indent in generated_jit). isort: 5-line .utils import block collapses to one line at 100-char limit. Cat 2 clean. Cat 5 grep clean."
 proximity,2026-06-18,,MEDIUM,4,"Re-audit 2026-06-18 (file last modified 2026-06-14). Cat 4 isort: from xrspatial.utils import (...) block wrapped one name early for line_length=100; pulled has_cuda_and_cupy onto first continuation line (both lines <=100, flake8 clean). isort+flake8 now clean. Fix applied + verified imports resolve. Cat 1/2/3 clean. Cat 5 grep: target_values: list = None on L1540/1700/1859 are type annotations not builtin-shadowing vars (false positive); mutable-default already None-sentinel from prior #2725. MEDIUM. /rockout issue+PR creation BLOCKED by auto-mode classifier (external publish denied); fix committed to deep-sweep branch only."

xrspatial/perlin.py

@@ -25,8 +25,8 @@ class cupy(object):
 from numba import cuda, jit
 
 # local modules
-from xrspatial.utils import (ArrayTypeFunctionMapping, _dask_task_name_kwargs,
-                             _validate_raster, cuda_args, not_implemented_func)
+from xrspatial.utils import (ArrayTypeFunctionMapping, _dask_task_name_kwargs, _validate_raster,
+                             cuda_args)
 
 
 def _make_perm_table(seed):