String formatting positional argument fix.

src/formdefinition.py

@@ -42,8 +42,8 @@ class FormDefinition(object):
         for field in fields:
             for prop_name in required:
                 if not prop_name in field:
-                    raise KeyError("Missing required property '{}' for field "
+                    raise KeyError("Missing required property '{0}' for field "
-                                   "'{}'".format(prop_name, str(field)))
+                                   "'{1}'".format(prop_name, str(field)))
 
     def get_field_def(self, field_name):
         """

src/formrender.py

@@ -24,7 +24,7 @@ HTML_FIELD_CHECKBOX = u'''
   </li>
 '''
 
-HTML_REQUIRED = u'{} <abbr title="This field is required" \
+HTML_REQUIRED = u'{0} <abbr title="This field is required" \
                 u"class="required">•</span>'
 
 

src/scriptform.py

@@ -237,7 +237,7 @@ def main():  # pragma: no cover
                 sys.exit(0)
         except socket.error as err:
             log.exception(err)
-            sys.stderr.write("Cannot bind to port {}: {}\n".format(
+            sys.stderr.write("Cannot bind to port {0}: {1}\n".format(
                 options.port,
                 str(err)
             ))

src/webserver.py

@@ -104,7 +104,7 @@ class RequestHandler(BaseHTTPRequestHandler):
             for header_k, header_v in err.headers.items():
                 self.send_header(header_k, header_v)
             self.end_headers()
-            self.wfile.write("Error {}: {}".format(err.status_code,
+            self.wfile.write("Error {0}: {1}".format(err.status_code,
                                                      err.msg))
             self.wfile.flush()
             return False