update extensions doc

docs/changelog/changes_07.rst

@@ -57,12 +57,14 @@ Changes in 0.7
   - Added support for enums :ref:`Check enums documentation <enums-doc>`
   - Added support for custom scalars :ref:`Check custom scalars documentation <scalars-doc>`
   - Added support for extensions :ref:`Check extensions documentation <extensions-doc>`
+
     - Added ``QueryParseCache`` extension - cache parsed graphql queries ast.
     - Added ``QueryTransformCache`` extension - cache transformed graphql ast into query Node.
     - Added ``QueryValidationCache`` extension - cache query validation.
     - Added ``QueryDepthValidator`` extension - validate query depth
     - Added ``PrometheusMetrics`` extension - wrapper around ``GraphMetrics`` visitor
     - Added ``PrometheusMetricsAsync`` extension - wrapper around ``AsyncGraphMetrics`` visitor
+
   - Add new method ``Engine.execute_context``, which accepts ``ExecutionContext``. ``Engine.execute`` now dispatches to ``Engine.execute_context``.
   - Add new method ``Engine.execute_mutation``, which allows to execute query against mutation graph
   - Add optional ``context`` argument to ``GraphqlEndpoint.dispatch`` method

docs/extensions.rst

@@ -36,10 +36,13 @@ Writing extension
 
 .. code-block:: python
 
-    from hiku.extensions import Extension
+    from typing import Iterator
+
+    from hiku.extensions.base_extension import Extension
+    from hiku.context import ExecutionContext
 
     class TimeItExtension(Extension):
-        def on_execute(self):
+        def on_execute(self, execution_context: ExecutionContext) -> Iterator[None]:
             start = time.perf_counter()
             yield
             print('Query execution took {:.3f} seconds'.format(time.perf_counter() - start))