fix: typing.Literal not working in python 3.7

Author: hfudev

pytest-embedded-idf/pytest_embedded_idf/utils.py

@@ -1,3 +1,4 @@
+import sys
 import typing as t
 from contextvars import ContextVar
 
@@ -9,6 +10,12 @@
 preview_targets = ContextVar('preview_targets', default=PREVIEW_TARGETS)
 
 
+if sys.version_info < (3, 8):
+    from typing_extensions import Literal
+else:
+    from typing import Literal
+
+
 def _expand_target_values(values: t.List[t.List[t.Any]], target_index: int) -> t.List[t.List[t.Any]]:
     """
     Expands target-specific values into individual test cases.
@@ -93,7 +100,7 @@ def decorator(func):
     return decorator
 
 
-ValidTargets = t.Literal['supported_targets', 'preview_targets', 'all']
+ValidTargets = Literal['supported_targets', 'preview_targets', 'all']
 
 
 def soc_filtered_targets(soc_statement: str, targets: ValidTargets = 'all') -> t.List[str]: