The open function has an optional second argument. This can be 'r',
for read-only access, 'w', for read-write access of an existing
-database, 'n' or 'c' for read-write access to a new database. The
-default is 'r'.
+database, 'c' for read-write access to a new or existing database, and
+'n' for read-write access to a new database. The default is 'r'.
-Note: the difference between 'w' and 'n' is that 'w' fails if the
-database doesn't already exist. There appears to be no difference
-between 'n' and 'c'.
+Note: 'r' and 'w' fail if the database doesn't exist; 'c' creates it
+only if it doesn't exist; and 'n' always creates a new database.
"""