fix typing imports for py3.7

Author: FynnBe

bioimageio/core/prediction_pipeline/_combined_processing.py

@@ -1,10 +1,8 @@
-import collections
 import warnings
 from collections import defaultdict
-from typing import Any, Dict, List, Literal, Optional, Sequence, Set, Tuple, Type
+from typing import Any, Dict, List, Optional, Sequence, Set, Tuple, Type
 
 import xarray as xr
-from marshmallow import missing
 
 from bioimageio.core.resource_io import nodes
 from bioimageio.core.statistical_measures import Mean, Measure, Percentile, Std
@@ -21,6 +19,10 @@
     ZeroMeanUnitVariance,
 )
 
+try:
+    from typing import Literal
+except ImportError:
+    from typing_extensions import Literal  # type: ignore
 
 KNOWN_PREPROCESSING: Dict[PreprocessingName, Type[Processing]] = {
     "binarize": Binarize,

bioimageio/core/prediction_pipeline/_processing.py

@@ -1,11 +1,16 @@
 from dataclasses import dataclass, field, fields
-from typing import Any, Dict, Literal, Optional, Sequence, Set, Union, get_args
+from typing import Any, Dict, Optional, Sequence, Set, Union
 
 import numpy as np
 import xarray as xr
 
 from bioimageio.core.statistical_measures import Mean, Measure, Percentile, Std
 
+try:
+    from typing import Literal, get_args
+except ImportError:
+    from typing_extensions import Literal, get_args  # type: ignore
+
 
 @dataclass
 class Processing: