First batch of signature documentation changes; using default argument syntax where applicable.
diff --git a/Doc/library/aifc.rst b/Doc/library/aifc.rst
index e3bb51a..182b121 100644
--- a/Doc/library/aifc.rst
+++ b/Doc/library/aifc.rst
@@ -37,7 +37,7 @@
Module :mod:`aifc` defines the following function:
-.. function:: open(file[, mode])
+.. function:: open(file, mode=None)
Open an AIFF or AIFF-C file and return an object instance with methods that are
described below. The argument *file* is either a string naming a file or a file