'Remove a tag from the handler based ond key and category.
Args:
key (str or list): The tag or tags to retrieve.
category (str, optional): The Tag category to limit the
request to. Note that `None` is the valid, default
category.'

def remove(self, key, category=None):

    for key in make_iter(key):
        if (not (key or key.strip())):
            continue
        tagstr = key.strip().lower()
        category = (category.strip().lower() if category else category)
        tagobj = getattr(self.obj, self._m2m_fieldname).filter(db_key=tagstr, db_category=category, db_model=self._model, db_tagtype=self._tagtype)
        if tagobj:
            getattr(self.obj, self._m2m_fieldname).remove(tagobj[0])
        self._delcache(key, category)
