imaplib AND date format

[harryos]

In imaplib.IMAP4.search() the search string SENTON can be used
'(SENTON 22-Jun-2010)'  .
But the RFC 2060 defines search key as
SENTON <date>  Messages whose [RFC-822] Date: header is within the
                     specified date.
and in RFC822 it is given as,
date        =  1*2DIGIT month 2DIGIT        ; day month year
                                                               ;  e.g.
20 Jun 82

The format 22 Jun 10 will cause aSEARCH command error:
 BAD ['Could not parse command']

Is this  deliberate or is it an anomaly ?
regards,
harry