diff --git a/PyPDF2/generic.py b/PyPDF2/generic.py
index 2f93d3c..959957d 100644
--- a/PyPDF2/generic.py
+++ b/PyPDF2/generic.py
@@ -363,7 +363,7 @@ def readStringFromStream(stream):
                            b_('$') : b_('$'),
                            }
             try:
-                tok = escape_dict[tok]
+                tok = ESCAPE_DICT[tok]
             except KeyError:
                 if tok.isdigit():
                     # "The number ddd may consist of one, two, or three