fix: remove unnecessary typing-extensions for py3.8

Author: Nadir Albajari

Diff for: aws_lambda_powertools/utilities/parser/models/dynamodb.py

@@ -2,7 +2,8 @@
 from typing import Any, Dict, List, Optional
 
 from pydantic import BaseModel
-from typing_extensions import Literal
+
+from ..types import Literal
 
 
 class DynamoDBStreamChangedRecordModel(BaseModel):

Diff for: aws_lambda_powertools/utilities/parser/models/kinesis.py

@@ -5,7 +5,8 @@
 
 from pydantic import BaseModel, validator
 from pydantic.types import PositiveInt
-from typing_extensions import Literal
+
+from ..types import Literal
 
 logger = logging.getLogger(__name__)
 

Diff for: aws_lambda_powertools/utilities/parser/models/s3.py

@@ -5,7 +5,8 @@
 from pydantic.fields import Field
 from pydantic.networks import IPvAnyNetwork
 from pydantic.types import PositiveInt
-from typing_extensions import Literal
+
+from ..types import Literal
 
 
 class S3EventRecordGlacierRestoreEventData(BaseModel):

Diff for: aws_lambda_powertools/utilities/parser/models/ses.py

@@ -4,7 +4,8 @@
 from pydantic import BaseModel, Field
 from pydantic.networks import EmailStr
 from pydantic.types import PositiveInt
-from typing_extensions import Literal
+
+from ..types import Literal
 
 
 class SesReceiptVerdict(BaseModel):

Diff for: aws_lambda_powertools/utilities/parser/models/sns.py

@@ -3,7 +3,8 @@
 
 from pydantic import BaseModel, root_validator
 from pydantic.networks import HttpUrl
-from typing_extensions import Literal
+
+from ..types import Literal
 
 
 class SnsMsgAttributeModel(BaseModel):

Diff for: aws_lambda_powertools/utilities/parser/models/sqs.py

@@ -2,7 +2,8 @@
 from typing import Dict, List, Optional
 
 from pydantic import BaseModel
-from typing_extensions import Literal
+
+from ..types import Literal
 
 
 class SqsAttributesModel(BaseModel):

Diff for: aws_lambda_powertools/utilities/parser/types.py

@@ -1,6 +1,16 @@
 """Generics and other shared types used across parser"""
+import sys
 from typing import TypeVar
 
 from pydantic import BaseModel
 
+# Workaround for not importing typing_extensions on python ^3.8
+if sys.version_info[0] > 3 or (sys.version_info[0] == 3 and sys.version_info[1] >= 8):
+    from typing import Literal  # noqa: F401
+else:
+    try:
+        from typing_extensions import Literal  # noqa: F401
+    except ImportError:
+        raise Exception("please install typing-extensions or upgrade to Python >= 3.8")
+
 Model = TypeVar("Model", bound=BaseModel)

Diff for: pyproject.toml

@@ -26,7 +26,7 @@ boto3 = "^1.12"
 jmespath = "^0.10.0"
 pydantic = {version = "^1.6.0", optional = true }
 email-validator = {version = "*", optional = true }
-typing_extensions = {version = "^3.7.4.2", optional = true }
+typing_extensions = {version = "^3.7.4.2", optional = true, python= "<3.8" }
 
 [tool.poetry.dev-dependencies]
 coverage = {extras = ["toml"], version = "^5.0.3"}

Diff for: tests/functional/parser/schemas.py

@@ -1,7 +1,6 @@
 from typing import Dict, List, Optional
 
 from pydantic import BaseModel
-from typing_extensions import Literal
 
 from aws_lambda_powertools.utilities.parser.models import (
     DynamoDBStreamChangedRecordModel,
@@ -14,6 +13,7 @@
     SqsModel,
     SqsRecordModel,
 )
+from aws_lambda_powertools.utilities.parser.types import Literal
 
 
 class MyDynamoBusiness(BaseModel):