Fix dynamic param tests.

jedi/evaluate/representation.py

@@ -78,6 +78,7 @@ class Instance(use_metaclass(CachedMetaClass, Executed)):
     This class is used to evaluate instances.
     """
     def __init__(self, evaluator, parent_context, class_context, var_args, is_generated=False):
+        raise DeprecationWarning
         super(Instance, self).__init__(evaluator, parent_context, var_args)
         # Generated instances are classes that are just generated by self
         # (No var_args) used.
@@ -562,14 +563,17 @@ class FunctionContext(use_metaclass(CachedMetaClass, context.TreeContext, Wrappe
         else:
             return function_execution.get_return_values()
 
-    @Python3Method
-    def py__call__(self, params):
-        function_execution = FunctionExecutionContext(
+    def get_function_execution(self, arguments):
+        return FunctionExecutionContext(
             self.evaluator,
             self.parent_context,
             self.base,
-            params
+            arguments
         )
+
+    @Python3Method
+    def py__call__(self, arguments):
+        function_execution = self.get_function_execution(arguments)
         return self.infer_function_execution(function_execution)
 
     def py__class__(self):