Add comment about "Google Colab" minimum "Python" version and "typing_extensions".
@@ -42,6 +42,7 @@ try:
SupportsIndex,
TypedDict,
)
+# TODO: Drop "typing_extensions" when "Google Colab" uses Python >= 3.8.
except ImportError: # pragma: no cover
from typing_extensions import ( # type: ignore[misc]
Literal,
