gistfile1.txt

diff --git a/src/core/Any.pm b/src/core/Any.pm
index d22ccfb..0d11246 100644
--- a/src/core/Any.pm
+++ b/src/core/Any.pm
@@ -306,25 +306,25 @@ my class Any {
     multi method postcircumfix:<{ }>(:$BIND!) {
         X::Bind::ZenSlice.new(type => self.WHAT).throw
     }
-    multi method postcircumfix:<{ }>(\SELF: $key) is rw {
+    multi method postcircumfix:<{ }>(\SELF: Mu $key) is rw {
         SELF.at_key($key)
     }
-    multi method postcircumfix:<{ }>(\SELF: $key, Mu :$BIND! is parcel) is rw {
+    multi method postcircumfix:<{ }>(\SELF: Mu $key, Mu :$BIND! is parcel) is rw {
         SELF.bind_key($key, $BIND)
     }
-    multi method postcircumfix:<{ }>(\SELF: $key, :$delete!) is rw {
+    multi method postcircumfix:<{ }>(\SELF: Mu $key, :$delete!) is rw {
         SELF.delete($key)
     }
-    multi method postcircumfix:<{ }>(\SELF: $key, :$exists!) is rw {
+    multi method postcircumfix:<{ }>(\SELF: Mu $key, :$exists!) is rw {
         SELF.exists($key)
     }
-    multi method postcircumfix:<{ }>(\SELF: $key, :$p!) is rw {
+    multi method postcircumfix:<{ }>(\SELF: Mu $key, :$p!) is rw {
         RWPAIR($key, SELF.at_key($key))
     }
-    multi method postcircumfix:<{ }>(\SELF: $key, :$k!) is rw {
+    multi method postcircumfix:<{ }>(\SELF: Mu $key, :$k!) is rw {
         $key
     }
-    multi method postcircumfix:<{ }>(\SELF: $key, :$kv!) is rw {
+    multi method postcircumfix:<{ }>(\SELF: Mu $key, :$kv!) is rw {
         ($key, SELF.at_key($key))
     }
     multi method postcircumfix:<{ }>(\SELF: Positional \key) is rw {