docs: def _open(self):
          """Bind, use tls"""
          try:
              self.ldap.start_tls_s()
          #pylint: disable=no-member
          except ldap.CONNECT_ERROR:
          #pylint: enable=no-member
              logging.error('Unable to establish a connection to the LDAP server, ' + \
                            'please check the connection string ' + \
                            'and ensure the remote certificate is signed by a trusted authority.')
              raise
  
          self.ldap.simple_bind_s(self.user, self.password)