code: def add_database_user(self, new_username, new_password, permissions=None):
          
          url = "db/{0}/users".format(self._database)
  
          data = {
              'name': new_username,
              'password': new_password
          }
  
          if permissions:
              try:
                  data['readFrom'], data['writeTo'] = permissions
              except (ValueError, TypeError):
                  raise TypeError(
                      "'permissions' must be (readFrom, writeTo) tuple"
                  )
  
          self.request(
              url=url,
              method='POST',
              data=data,
              expected_response_code=200
          )
  
          return True
docs: Add database user.
  
          :param permissions: A ``(readFrom, writeTo)`` tuple