'`True` if the card is completely blank--that is, it has no keyword,
value, or comment.  It appears in the header as 80 spaces.
Returns `False` otherwise.'

@property
def is_blank(self):

    if (not self._verified):
        return (self._image == BLANK_CARD)
    return ((not self.keyword) and (isinstance(self.value, string_types) and (not self.value)) and (not self.comment))
