code: async def ehlo(self, from_host=None):
          
          if from_host is None:
              from_host = self.fqdn
  
          code, message = await self.do_cmd("EHLO", from_host)
  
          self.last_ehlo_response = (code, message)
  
          extns, auths = SMTP.parse_esmtp_extensions(message)
          self.esmtp_extensions = extns
          self.auth_mechanisms = auths
          self.supports_esmtp = True
  
          return code, message
docs: Sends a SMTP 'EHLO' command. - Identifies the client and starts the
          session.
  
          If given ``from`_host`` is None, defaults to the client FQDN.
  
          For further details, please check out `RFC 5321 § 4.1.1.1`_.
  
          Args:
              from_host (str or None): Name to use to identify the client.
  
          Raises:
              ConnectionResetError: If the connection with the server is
                  unexpectedely lost.
              SMTPCommandFailedError: If the server refuses our EHLO greeting.
  
          Returns:
              (int, str): A (code, message) 2-tuple containing the server
                  response.
  
          .. _`RFC 5321 § 4.1.1.1`: https://tools.ietf.org/html/rfc5321#section-4.1.1.1