':return: True if entry is valid. Return False if this cannot be used.
:rtype: bool'

def isvalid(self):

    if (u'title' not in self):
        return False
    if (u'url' not in self):
        return False
    if (not isinstance(self[u'url'], str)):
        return False
    if (not isinstance(self[u'title'], str)):
        return False
    return True
