diff --git a/generator/Data/XCB/Python/Parse.hs b/generator/Data/XCB/Python/Parse.hs
--- a/generator/Data/XCB/Python/Parse.hs
+++ b/generator/Data/XCB/Python/Parse.hs
@@ -294,6 +294,7 @@
 structElemToPyUnpack _ _ _ (Doc _ _ _) = Left (Nothing, "")
 -- XXX: What does fd mean? we should implement it correctly
 structElemToPyUnpack _ _ _ (Fd _) = Left (Nothing, "")
+structElemToPyUnpack _ _ _ (Length _ _) = Left (Nothing, "")
 
 -- The switch fields pick the way to expression to pack based on the expression
 structElemToPyUnpack _ _ _ (Switch name expr _ bitcases) =
@@ -352,9 +353,10 @@
                                                                      [(Expr (), [GenStructElem Type])]
                                                     )]
 structElemToPyPack _ _ _ (Pad i) = Left (Nothing, mkPad i)
--- TODO: implement doc and fd?
+-- TODO: implement these?
 structElemToPyPack _ _ _ (Doc _ _ _) = Left (Nothing, "")
 structElemToPyPack _ _ _ (Fd _) = Left (Nothing, "")
+structElemToPyPack _ _ _ (Length _ _) = Left (Nothing, "")
 structElemToPyPack _ _ accessor (Switch n expr _ bitcases) =
   let name = accessor n
       cmp = xExpressionToPyExpr id expr
@@ -646,6 +648,7 @@
       getName (Switch n _ _ _) = Just n
       getName (Doc _ _ _) = Nothing
       getName (Fd n) = Just n
+      getName (Length _ _) = Nothing
 
       assign :: String -> Statement ()
       assign n = mkAssign (mkDot "self" n) $ mkName n
diff --git a/xcffib.cabal b/xcffib.cabal
--- a/xcffib.cabal
+++ b/xcffib.cabal
@@ -1,5 +1,5 @@
 name:                xcffib
-version:             0.11.1
+version:             0.12.0
 synopsis:            A cffi-based python binding for X
 homepage:            http://github.com/tych0/xcffib
 license:             OtherLicense
@@ -25,7 +25,7 @@
 
 library
   build-depends: base ==4.*,
-                 xcb-types >= 0.10.0,
+                 xcb-types >= 0.11.0,
                  language-python >= 0.5.6,
                  filepath,
                  filemanip,
@@ -48,7 +48,7 @@
                  xcffib,
                  language-python >= 0.5.6,
                  split,
-                 xcb-types >= 0.10.0,
+                 xcb-types >= 0.11.0,
                  optparse-applicative >= 0.13,
                  filepath,
                  filemanip,
@@ -83,7 +83,7 @@
   type: exitcode-stdio-1.0
   build-depends: base ==4.*,
                  xcffib,
-                 xcb-types >= 0.10.0,
+                 xcb-types >= 0.11.0,
                  language-python >= 0.5.6,
                  HUnit,
                  test-framework,