def __init__(self, parentIssue, commentelem, mapToBE={}, dontprocess=set(), mapFromBE=None):
"""Initialises a new comment taken from an XML backing. mapToBE should be a dictionary
mapping the source XML element tags to BE element names and outputs if necessary i.e
mapToBE={'xmltag':('befield', lambda xmlelem:xmlelem.text)}
Current BE comment fields:
uuid: UUID
[Alt-id]: string
[short-name]: string
[In-reply-to]: UUID
Author: string
Date: datetime string
Content-type: mimetype string
body: string
"""
if mapFromBE is None: mapFromBE={v[0]:(k, v[1]) for k, v in mapToBE.iteritems()}
CommentBase.__init__(self, parentIssue)
self.__element=commentelem
self.__elementhash=0
self.__mapToBE=mapToBE
self.__dontprocess=dontprocess
self.__mapFromBE=mapFromBE
self.__setUUID()