Fix _graph_utils import (#2675)

src/sdk/pynni/nni/compression/torch/speedup/compressor.py

@@ -3,7 +3,6 @@
 
 import logging
 import torch
-from nni._graph_utils import build_module_graph
 from nni.compression.torch.utils.mask_conflict import fix_mask_conflict
 from .compress_modules import replace_module
 from .infer_shape import ModuleMasks, infer_from_mask, infer_from_inshape, infer_from_outshape
@@ -51,6 +50,8 @@ class ModelSpeedup:
         map_location : str
             the device on which masks are placed, same to map_location in ```torch.load```
         """
+        from nni._graph_utils import build_module_graph
+
         self.bound_model = model
         self.masks = torch.load(masks_file, map_location)
         self.inferred_masks = dict() # key: module_name, value: ModuleMasks

src/sdk/pynni/nni/compression/torch/utils/shape_dependency.py

@@ -4,8 +4,6 @@
 import csv
 import logging
 
-from nni._graph_utils import TorchModuleGraph
-
 __all__ = ['ChannelDependency', 'GroupDependency', 'CatPaddingDependency']
 
 CONV_TYPE = 'aten::_convolution'
@@ -19,6 +17,8 @@ class Dependency:
         """
         Build the graph for the model.
         """
+        from nni._graph_utils import TorchModuleGraph
+
         # check if the input is legal
         if traced_model is None:
             # user should provide model & dummy_input to trace