remove typing_extensions dependency (#1992)

Co-authored-by: Adeel Hassan <ahassan@element84.com>

rastervision_core/rastervision/core/box.py

@@ -1,6 +1,5 @@
-from typing import (TYPE_CHECKING, Callable, Dict, List, Optional, Sequence,
-                    Tuple, Union)
-from typing_extensions import Literal
+from typing import (TYPE_CHECKING, Callable, Dict, List, Literal, Optional,
+                    Sequence, Tuple, Union)
 from pydantic import PositiveInt as PosInt, conint
 import math
 import random

rastervision_core/rastervision/core/rv_pipeline/semantic_segmentation_config.py

@@ -1,5 +1,4 @@
-from typing import (List, Optional, Union)
-from typing_extensions import Literal
+from typing import (List, Literal, Optional, Union)
 from pydantic import conint
 from enum import Enum
 

rastervision_pipeline/rastervision/pipeline/config.py

@@ -1,13 +1,12 @@
-from typing import List, Type, Union, Optional, Callable, Dict, TYPE_CHECKING
+from typing import (TYPE_CHECKING, Callable, Dict, List, Literal, Optional,
+                    Type, Union)
 import inspect
 import logging
 
 from pydantic import (  # noqa
     BaseModel, create_model, Field, root_validator, validate_model,
     ValidationError, validator)
 
-from typing_extensions import Literal
-
 from rastervision.pipeline import (registry_ as registry, rv_config_ as
                                    rv_config)
 from rastervision.pipeline.file_system import str_to_file

rastervision_pipeline/requirements.txt

@@ -1,6 +1,5 @@
 click==8.1.3
 pydantic==1.10.7
-typing_extensions==4.6.3
 everett==3.2.0
 everett[ini]==3.2.0
 six==1.16.*

rastervision_pytorch_learner/rastervision/pytorch_learner/dataset/dataset.py

@@ -1,5 +1,4 @@
-from typing import Union, Optional, Tuple, Any, TypeVar
-from typing_extensions import Literal
+from typing import Any, Literal, Optional, Tuple, TypeVar, Union
 import logging
 
 import numpy as np

rastervision_pytorch_learner/rastervision/pytorch_learner/learner.py

@@ -1,6 +1,5 @@
 from typing import (TYPE_CHECKING, Any, Callable, Dict, Iterator, List,
-                    Optional, Tuple, Union, Type)
-from typing_extensions import Literal
+                    Literal, Optional, Tuple, Union, Type)
 from abc import ABC, abstractmethod
 from os.path import join, isfile, basename, isdir
 import warnings

rastervision_pytorch_learner/rastervision/pytorch_learner/learner_config.py

@@ -5,8 +5,7 @@
 import logging
 
 from typing import (TYPE_CHECKING, Any, Callable, Dict, Iterable, List,
-                    Optional, Sequence, Tuple, Union)
-from typing_extensions import Literal
+                    Literal, Optional, Sequence, Tuple, Union)
 from pydantic import (PositiveFloat, PositiveInt as PosInt, constr, confloat,
                       conint)
 from pydantic.utils import sequence_like