diff --git a/pwndbg/commands/heap.py b/pwndbg/commands/heap.py
index 1e2c55212..d0503990a 100644
--- a/pwndbg/commands/heap.py
+++ b/pwndbg/commands/heap.py
@@ -1,5 +1,6 @@
 import argparse
 import ctypes
+from string import printable
 from typing import Dict
 from typing import List
 
@@ -973,11 +974,11 @@ def vis_heap_chunks(
         )
 
 
-def bin_ascii(bs):
-    from string import printable
+VALID_CHARS = list(map(ord, set(printable) - set("\t\r\n\x0c\x0b")))
+
 
-    valid_chars = list(map(ord, set(printable) - set("\t\r\n\x0c\x0b")))
-    return "".join(chr(c) if c in valid_chars else "." for c in bs)
+def bin_ascii(bs):
+    return "".join(chr(c) if c in VALID_CHARS else "." for c in bs)
 
 
 def bin_labels_mapping(collections):