diff --git a/pmb/core/arch.py b/pmb/core/arch.py
index 6f370f20..6242a784 100644
--- a/pmb/core/arch.py
+++ b/pmb/core/arch.py
@@ -80,19 +80,16 @@ class Arch(enum.Enum):
         specify architectures supported by Alpine here. For cross-compiling,
         we need to generate the "musl-$ARCH" and "gcc-$ARCH" packages (use
         "pmbootstrap aportgen musl-armhf" etc.)."""
-        # FIXME: cache?
-        return set(
-            [
-                Arch.armhf,
-                Arch.armv7,
-                Arch.aarch64,
-                Arch.x86_64,
-                Arch.x86,
-                Arch.riscv64,
-                Arch.ppc64le,
-                Arch.native(),
-            ]
-        )
+        return {
+            Arch.armhf,
+            Arch.armv7,
+            Arch.aarch64,
+            Arch.x86_64,
+            Arch.x86,
+            Arch.riscv64,
+            Arch.ppc64le,
+            Arch.native(),
+        }
 
     # FIXME: we should use pmaports.cfg "supported_arches" instead
     @staticmethod