Latex Plugin Crashes due to missing attribute/property

  File "/home/webpigeon/.local/share/virtualenvs/errbot-CvTTjbXc/lib/python3.9/site-packages/errbot/core.py", line 552, in _execute_and_send
    reply = method(msg, match) if match else method(msg, args)
  File "/home/webpigeon/Documents/fossgalaxy/projects/errbot/test/data/plugins/samueldg/err-latex/latex.py", line 25, in latex
    self.send_card(
  File "/home/webpigeon/.local/share/virtualenvs/errbot-CvTTjbXc/lib/python3.9/site-packages/errbot/botplugin.py", line 631, in send_card
    self._bot.send_card(
  File "/home/webpigeon/.local/share/virtualenvs/errbot-CvTTjbXc/lib/python3.9/site-packages/errbot/core.py", line 231, in send_card
    self.send_templated(card.to, "card", {"card": card})
  File "/home/webpigeon/.local/share/virtualenvs/errbot-CvTTjbXc/lib/python3.9/site-packages/errbot/core.py", line 201, in send_templated
    return self.send(identifier, text, in_reply_to, groupchat_nick_reply)
  File "/home/webpigeon/.local/share/virtualenvs/errbot-CvTTjbXc/lib/python3.9/site-packages/errbot/core.py", line 168, in send
    msg.frm = in_reply_to.to if in_reply_to else self.bot_identifier
AttributeError: 'MatrixBackend' object has no attribute 'bot_identifier'