ultralytics 8.0.20 CLI yolo simplifications, DDP and ONNX fixes (#608)

Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>
Co-authored-by: Sid Prabhakaran <s2siddhu@gmail.com>

ultralytics/yolo/v8/segment/val.py

@@ -1,6 +1,7 @@
 # Ultralytics YOLO 🚀, GPL-3.0 license
 
 import os
+import sys
 from multiprocessing.pool import ThreadPool
 from pathlib import Path
 
@@ -242,10 +243,17 @@ class SegmentationValidator(DetectionValidator):
         return stats
 
 
-def val(cfg=DEFAULT_CFG):
-    cfg.data = cfg.data or "coco128-seg.yaml"
-    validator = SegmentationValidator(args=cfg)
-    validator(model=cfg.model)
+def val(cfg=DEFAULT_CFG, use_python=False):
+    model = cfg.model or "yolov8n-seg.pt"
+    data = cfg.data or "coco128-seg.yaml"
+
+    args = dict(model=model, data=data, verbose=True)
+    if use_python:
+        from ultralytics import YOLO
+        YOLO(model).val(**args)
+    else:
+        validator = SegmentationValidator(args=args)
+        validator(model=args['model'])
 
 
 if __name__ == "__main__":