Merge pull request #128 from makenv/fix-oneflow-quantize

避免quantization在缺少oneflow模块的时候出错.

codegeex/quantization/__init__.py

@@ -1,3 +1,6 @@
 from .quantize import quantize
-from .quantize_oneflow import quantize_oneflow
-from .quantize_oneflow import QuantizedLinear
+try:
+    from .quantize_oneflow import quantize_oneflow
+    from .quantize_oneflow import QuantizedLinear
+except ModuleNotFoundError:
+    pass