move hapic.set_context method

hapic/hapic.py

     def context(self) -> ContextInterface:
         return self._context
 
+    def set_context(self, context: ContextInterface) -> None:
+        assert not self._context
+        self._context = context
+
     def with_api_doc(self):
         def decorator(func):
             @functools.wraps(func)
 
         return decorator
 
-    def set_context(self, context: ContextInterface) -> None:
-        assert not self._context
-        self._context = context
-
     def output_body(
         self,
         schema: typing.Any,