'Mark a message for deletion.
This must not change the number of messages in this mailbox.  Further
requests for the size of the deleted message should return 0.  Further
requests for the message itself may raise an exception.
@type i: L{int}
@param i: The 0-based index of a message.
@raise ValueError or IndexError: When the index does not correspond to
a message in the mailbox.  The use of ValueError is preferred.'

def deleteMessage(self, i):

    raise ValueError
