diff --git a/src/babashka/impl/proxy.clj b/src/babashka/impl/proxy.clj
new file mode 100644
index 00000000..59bfec91
--- /dev/null
+++ b/src/babashka/impl/proxy.clj
@@ -0,0 +1,18 @@
+(ns babashka.impl.proxy
+  {:no-doc true}
+  (:require [sci.impl.types]))
+
+(set! *warn-on-reflection* false)
+
+(defn method-or-bust [methods k]
+  (or (get methods k)
+      (throw (UnsupportedOperationException. "Method not implemented: " k))))
+
+(defn proxy-fn [{:keys [:class :methods]}]
+  (case (.getName ^Class class)
+    "clojure.lang.APersistentMap"
+    (proxy [clojure.lang.APersistentMap] []
+      (seq [] ((method-or-bust methods 'seq)))
+      (valAt
+        ([k] ((method-or-bust methods 'valAt) k))
+        ([k default] ((method-or-bust methods 'valAt) k default))))))