Try to introduce is_instance and is_function

jedi/evaluate/base_context.py

@@ -132,6 +132,12 @@ class Context(HelperContextMixin, BaseContext):
     def is_class(self):
         return False
 
+    def is_instance(self):
+        return False
+
+    def is_function(self):
+        return False
+
     def py__bool__(self):
         """
         Since Wrapper is a super class for classes, functions and modules,