diff --git a/jedi/parsing.py b/jedi/parsing.py
index af17df34..b3f20e92 100644
--- a/jedi/parsing.py
+++ b/jedi/parsing.py
@@ -709,7 +709,7 @@ class Statement(Simple):
                 raise
             else:
                 if tok in ['return', 'yield'] or level == 0 and \
-                        '=' in tok and not tok in ['>=', '<=', '==', '!=']:
+                    tok.endswith('=') and not tok in ['>=', '<=', '==', '!=']:
                     # This means, there is an assignment here.
 
                     # Add assignments, which can be more than one
diff --git a/test/completion/types.py b/test/completion/types.py
index 1dfc11b2..a29c1511 100644
--- a/test/completion/types.py
+++ b/test/completion/types.py
@@ -20,6 +20,11 @@ float.is_int
 #? ['upper']
 r"".upper
 
+# strangely this didn't work, because the = is used for assignments
+#? ['upper']
+"=".upper
+
+
 # -----------------
 # lists
 # -----------------