'Return an in-memory file-like object with the contents of a message.
@type i: L{int}
@param i: The 0-based index of a message.
@rtype: L{StringIO <cStringIO.StringIO>}
@return: An in-memory file-like object containing the message.
@raise IndexError: When the index does not correspond to a message in
the mailbox.'

def getMessage(self, i):

    return StringIO.StringIO(self.msgs[i])
