diff --git a/mangum/adapter.py b/mangum/adapter.py
index 61fb4293..9d67486d 100644
--- a/mangum/adapter.py
+++ b/mangum/adapter.py
@@ -11,6 +11,8 @@
 from mangum.protocols.http import HTTPCycle
 from mangum.exceptions import ConfigurationError
 
+if typing.TYPE_CHECKING:  # pragma: no cover
+    from awslambdaric.lambda_context import LambdaContext
 
 DEFAULT_TEXT_MIME_TYPES = [
     "application/json",
@@ -79,7 +81,7 @@ def __post_init__(self, text_mime_types: typing.Optional[typing.List[str]]) -> N
             text_mime_types = DEFAULT_TEXT_MIME_TYPES
         self.text_mime_types = text_mime_types
 
-    def __call__(self, event: dict, context: dict) -> dict:
+    def __call__(self, event: dict, context: "LambdaContext") -> dict:
         self.logger.debug("Event received.")
 
         with ExitStack() as stack:
diff --git a/requirements.txt b/requirements.txt
index 12a49bba..82ef74e7 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -9,6 +9,7 @@ moto
 mypy
 brotli
 brotli-asgi
+awslambdaric-stubs
 # Docs
 mkdocs
-mkdocs-material
\ No newline at end of file
+mkdocs-material