--- a/httpbin/helpers.py
+++ b/httpbin/helpers.py
@@ -30,7 +30,7 @@
 from .structures import CaseInsensitiveDict
 
 
-ASCII_ART = """
+ASCII_ART = r"""
     -=[ teapot ]=-
 
        _...._
@@ -75,7 +75,7 @@
     'image/*'
 ]
 
-ANGRY_ASCII ="""
+ANGRY_ASCII = r"""
           .-''''''-.
         .' _      _ '.
        /   O      O   \\
@@ -442,7 +442,7 @@
     if header_str:
         parts = header_str.split(',')
         for part in parts:
-            match = re.search('\s*(W/)?\"?([^"]*)\"?\s*', part)
+            match = re.search(r'\s*(W/)?\"?([^"]*)\"?\s*', part)
             if match is not None:
                 parsed_parts.append(match.group(2))
     return parsed_parts