diff --git a/pydoorlock/Door.py b/pydoorlock/Door.py
index f2e0849..09b0da4 100644
--- a/pydoorlock/Door.py
+++ b/pydoorlock/Door.py
@@ -23,6 +23,7 @@ class DoorState(Enum):
     Present = 1
     Closed = 2
 
+    @staticmethod
     def from_string(string):
         if string == 'lock':
             return DoorState.Closed