diff --git a/pytiled_parser/xml_parser.py b/pytiled_parser/xml_parser.py
index 6eed39a..db3a7df 100644
--- a/pytiled_parser/xml_parser.py
+++ b/pytiled_parser/xml_parser.py
@@ -182,10 +182,7 @@ def _parse_layer(
     Returns:
         FIXME
     """
-    if "id" in layer_element.attrib:
-        id_ = int(layer_element.attrib["id"])
-    else:
-        id_ = None
+    id_ = int(layer_element.attrib["id"])
 
     if "name" in layer_element.attrib:
         name = layer_element.attrib["name"]