Use new optional argument style in email docs.
diff --git a/Doc/library/email.parser.rst b/Doc/library/email.parser.rst
index ec2e71b..3de5c31 100644
--- a/Doc/library/email.parser.rst
+++ b/Doc/library/email.parser.rst
@@ -58,13 +58,12 @@
 Here is the API for the :class:`FeedParser`:
 
 
-.. class:: FeedParser([_factory])
+.. class:: FeedParser(_factory=email.message.Message)
 
    Create a :class:`FeedParser` instance.  Optional *_factory* is a no-argument
    callable that will be called whenever a new message object is needed.  It
    defaults to the :class:`email.message.Message` class.
 
-
    .. method:: feed(data)
 
       Feed the :class:`FeedParser` some more data.  *data* should be a string
@@ -74,7 +73,6 @@
       carriage return, newline, or carriage return and newline (they can even be
       mixed).
 
-
    .. method:: close()
 
       Closing a :class:`FeedParser` completes the parsing of all previously fed
@@ -96,7 +94,7 @@
 class.
 
 
-.. class:: Parser([_class])
+.. class:: Parser(_class=email.message.Message, strict=None)
 
    The constructor for the :class:`Parser` class takes an optional argument
    *_class*.  This must be a callable factory (such as a function or a class), and
@@ -115,7 +113,7 @@
    The other public :class:`Parser` methods are:
 
 
-   .. method:: parse(fp[, headersonly])
+   .. method:: parse(fp, headersonly=False)
 
       Read all the data from the file-like object *fp*, parse the resulting
       text, and return the root message object.  *fp* must support both the
@@ -129,7 +127,7 @@
 
       Optional *headersonly* is as with the :meth:`parse` method.
 
-   .. method:: parsestr(text[, headersonly])
+   .. method:: parsestr(text, headersonly=False)
 
       Similar to the :meth:`parse` method, except it takes a string object
       instead of a file-like object.  Calling this method on a string is exactly
@@ -147,14 +145,14 @@
 
 .. currentmodule:: email
 
-.. function:: message_from_string(s[, _class[, strict]])
+.. function:: message_from_string(s[, _class][, strict])
 
    Return a message object structure from a string.  This is exactly equivalent to
    ``Parser().parsestr(s)``.  Optional *_class* and *strict* are interpreted as
    with the :class:`Parser` class constructor.
 
 
-.. function:: message_from_file(fp[, _class[, strict]])
+.. function:: message_from_file(fp[, _class][, strict])
 
    Return a message object structure tree from an open file object.  This is
    exactly equivalent to ``Parser().parse(fp)``.  Optional *_class* and *strict*