diff --git a/python/helpers/pydev/_pydevd_bundle/pydevd_signature.py b/python/helpers/pydev/_pydevd_bundle/pydevd_signature.py
index d8476199c233..8203abca50f4 100644
--- a/python/helpers/pydev/_pydevd_bundle/pydevd_signature.py
+++ b/python/helpers/pydev/_pydevd_bundle/pydevd_signature.py
@@ -169,17 +169,18 @@ def create_signature_message(signature):
 def send_signature_call_trace(dbg, frame, filename):
     if dbg.signature_factory and dbg.signature_factory.is_in_scope(filename):
         signature = dbg.signature_factory.create_signature(frame)
-        if dbg.signature_factory.cache is not None:
-            if not dbg.signature_factory.cache.is_in_cache(signature):
-                dbg.signature_factory.cache.add(signature)
+        if signature is not None:
+            if dbg.signature_factory.cache is not None:
+                if not dbg.signature_factory.cache.is_in_cache(signature):
+                    dbg.signature_factory.cache.add(signature)
+                    dbg.writer.add_command(create_signature_message(signature))
+                    return True
+                else:
+                    # we don't send signature if it is cached
+                    return False
+            else:
                 dbg.writer.add_command(create_signature_message(signature))
                 return True
-            else:
-                # we don't send signature if it is cached
-                return False
-        else:
-            dbg.writer.add_command(create_signature_message(signature))
-            return True
     return False
 
 
diff --git a/python/helpers/pydev/_pydevd_bundle/pydevd_utils.py b/python/helpers/pydev/_pydevd_bundle/pydevd_utils.py
index 9b2ca6733fa2..bb5067a882bf 100644
--- a/python/helpers/pydev/_pydevd_bundle/pydevd_utils.py
+++ b/python/helpers/pydev/_pydevd_bundle/pydevd_utils.py
@@ -157,20 +157,21 @@ def get_clsname_for_code(code, frame):
         func_name = code.co_name
         if len(code.co_varnames) > 0:
             first_arg_name = code.co_varnames[0]
-            first_arg_obj = frame.f_locals[first_arg_name]
-            if inspect.isclass(first_arg_obj):  # class method
-                first_arg_class = first_arg_obj
-            else:  # instance method
-                first_arg_class = first_arg_obj.__class__
-            if hasattr(first_arg_class, func_name):
-                method = getattr(first_arg_class, func_name)
-                func_code = None
-                if hasattr(method, 'func_code'):  # Python2
-                    func_code = method.func_code
-                elif hasattr(method, '__code__'):  # Python3
-                    func_code = method.__code__
-                if func_code and func_code == code:
-                    clsname = first_arg_class.__name__
+            if first_arg_name in frame.f_locals:
+                first_arg_obj = frame.f_locals[first_arg_name]
+                if inspect.isclass(first_arg_obj):  # class method
+                    first_arg_class = first_arg_obj
+                else:  # instance method
+                    first_arg_class = first_arg_obj.__class__
+                if hasattr(first_arg_class, func_name):
+                    method = getattr(first_arg_class, func_name)
+                    func_code = None
+                    if hasattr(method, 'func_code'):  # Python2
+                        func_code = method.func_code
+                    elif hasattr(method, '__code__'):  # Python3
+                        func_code = method.__code__
+                    if func_code and func_code == code:
+                        clsname = first_arg_class.__name__
     return clsname